Just completed one week in Montreal and I hit many great places thanks to recommendations by other Chowhounders. Many thanks to all posters for their thoughts. Here's my (extremely long) take as a visitor, and a few tips that may help future first-time visitors.
Best things I ate and drank (no particular order):
Sesame bagels at Fairmount (decisively over St. Viateur)
Fried smelt at Aqua-Mare at Jean Talon market
Grilled mackerel and roasted cauliflower appetizer at Joe Beef
Strawberry panna cotta (yeah, who'd have thunk it?) at Au Pied De Cochon
Haricots fins salad at Leméac
Pita sandwiches (one chicken, one falafel) at Boustan
Montreal smoked meat sandwich from Main (upset!)
Blanche de Chambly on tap at NYK pub.
A crémant from Jura at Buchonné
Visit summary (no particular order):
Bagels: Fresh warm sesame bagels were a total revelation. Amazing. I liked Fairmount significantly better than St. Viateur for immediate consumption. They struck me as a bit crustier and chewier, which I liked. St. Viateur seemed softer. One thing that nobody warns you: there's a wide range of doneness - some light, some dark, some very dark. You can ask for it the way you want (I preferred dark but I heard others ask for "not too dark"). Oddly, I brought some back for my brother and he said he thought St. Viateur was better when he visited, but he liked Fairmount better as well this time (although here the taste test was of 18-hour olds rather than fresh from the bakery). I hit these places a number of times each so it wasn't a one-off issue, for sure. And I'll say that when they tell you that you don't need any cream cheese or whatever to go with the bagel - they're absolutely right! Delicious plain. Didn't try anything but sesame, however. Couldn't convince myself to go off that beaten path.
Jean Talon Market: I didn't leave nearly enough time to wander around and graze. There's a ton of options and many look good. I got the combo fried calamari/smelt at Aqua-Mare. Calamari was meh. The smelt was amazing.
Au Pied De Cochon: Oddly, while I enjoyed the seriously meat-centric dishes, the dishes that really wowed me were a fava bean appetizer and a strawberry panna cotta. The latter had the most unbelieveable micro-basil that was the best basil I've ever had. Duck in a can, poutine (regular, not fois gras) and the Pudding Chômeur dessert were also tasty. I tried the fish of the day (halibut) but found the accompanying foam too buttery-rich for me. I do think it would be fun to work through the menu to find the things that I like the most (although I'm not sure I could morally justify frequent consumption of fois gras).
Boustan: Warning for the uninitiated: the line moves fast and you could be up well before you think you ought to be. Based on people ordering ahead of me, it seemed like one sandwich was not a lot of food, and it really wasn't. I audibled and ended up getting two pita sandwiches: one chicken and one falafel. Both were terrific, and was a good amount of food. I would totally eat there all the time if I lived in Montreal. The grilling of the whole package after construction is brilliant and brings a whole crispy and warm dimension to it that's key. If you want spicy, tell him as soon as he starts making it. I got spicy on one (falafel) and think it would have made the chicken one even better. By the way, they serve some soft drink called Brio which I'd never seen. I didn't try it - can anyone clue me in as to what this is about?
Leméac: I actually sat down at Buchonné to have dinner on my last night, but one look at the menu and something that seemed to occur way too often in Montreal happened again: there wasn't a single dish that was principally composed of vegetables. This happened at Joe Beef and APC as well, and I find it odd that one can't even get a simple salad, especially during the summer when the markets are overflowing with nice produce. So I did the very odd thing of walking out without ordering anything from Buchonné and went over to Leméac where I hoped my luck would change. And indeed, I got two dishes: a salad with haricots fins, sliced almonds and cherry tomatoes and the duck confit with roasted potatoes and salad. The first was terrific. Fresh, bright and simple. Only complaint might be a bit too much finishing olive oil, but it was high quality so it didn't get in the way of the primary ingredients. The second was also delicious. The roast potatoes were perfect, and the salad was also quite nice (again, too much oil used for dressing but I got over it). The confit was rich and flavorful, maybe not texturally perfect but very satisfying. I was a bit puzzled by my pour of wine by the glass. I noticed that some places in Montreal consider a 4 oz pour normal (I'm accustomed to 5 oz pours myself), but this was definitely shy of that, 3 to 3.5 oz, tops. Seemed rather stingy and didn't make me inclined to positive thoughts towards my server. In any case, such is probably an anomaly and I'd definitely go back and try other menu options.
Ramados: Portugese grilled chicken. I missed any previous posts that might have warned about the potential of them running out. I saw them run out right around 8 pm the night I was there, so make sure to go on the early side to be safe. Chicken was pretty good, maybe a bit overdone for my taste. Good grilled flavor and still falling-apart meat, though. Couldn't finish my fries. Even though I only got the quarter chicken (leg, or "cuisse"), it was more meat than just drumstick and thigh. I got an extra couple of smallish pieces which made it not only a great deal for $6, but also more than enough food for all but the hungriest eaters. I say this because I was pretty tempted to spend the extra couple of dollars to get a half chicken but I'm glad I didn't.
Buchonné: had an app and a glass of wine. The charcuterie plate was rather generous, and I'd describe it as more rustic than refined. The glass of wine (a crémant from Jura) was terrific.
Olive et Gourmando: Went for breakfast. Got a croissant and a morning muffin. Croissant was above average but not worth returning for. Morning muffin was rather nice. I'd get that again.
Fous Desserts: Grabbed a croissant to go. As one previous poster had said, it's the crispiest croissant you'll ever have, and I think it was meant in a good way. It was true, but I didn't find it that compelling. I prefer flaky over crispy, and none of the ones I had in Montreal really had this quality. Odd. I'm mow wishing I'd tried the chocolatine instead. Their other stuff looked terrific.
Joe Beef: First off, loved the chalkboard menu + wine list (there is no paper version from what I could tell). Very cool. Lots of good options and shared an appetizer of grilled mackeral and roasted cauliflower. That was a real winner. Great flavors. My main dish of a beautifully-cooked duck breast and fried polenta was simple and delicious. My friend's bavette steak was also tasty. Not cheap, and not super fancy food, but high quality ingredients and strong execution make it a winner. I'd go back but maybe would try the other related joints first just to scope out the overall scene (they're all on the same block).
La Banquise: I love fries and gravy. Having grown up in Canada, it's one of those things that I miss greatly now that I live in the US. That said, I'm not so sure I'm really sold on poutine. The cheese curds are just too squeaky/firm. If I were to design this dish from the ground up, I'd definitely go with some kind of melty cheese, as in chili-cheese fries with gravy instead of chili. I swear this would be tastier. In any case, I tried the choux poutine (coleslaw) and it was good. The cool slaw was a good counter point to the rich poutine.
Juliette et Chocolate: I tried the brownie with fleur de sel caramel. Brownie was very moist and dense. The caramel sauce was good, but I feel like I can do about as well at home so I wouldn't necessarily get it again now that I've seen the idea.
Montreal smoked meat: I went to both Schwartz's and Main (across the street). I think I preferred Main, but the two meals were far apart enough that I wouldn't swear by it. I thought the beef flavor was just a bit smoother. Main also has a totally different feel. Friendlier and less bustle. We went to the Schwartz's takeout section - the line that lives permanently on the sidwalk is, I believe, a wait for the sit down restaurant part; the takeout deli is next door and seems to have a much shorter line. In fact, my friends and I arrived at around 12:45 pm and there was zero line, although 5 min later it got to maybe 6 people long. The line seemed to move very fast, though, so don't be discouraged. The takeout storefront does have shorter hours than than the main deli, though, so this isn't always an option.
Beauty Luncheonette: lots of things looked terrific, but I had blintzes based on one recommendation. I'm not an experienced blintz eater, but these were yummy. Lightly crispy outside and a tangy and not-too-sweet cheese filling inside. Excellent. Looks like it would be great to work through their menu.
Dieu du Ciel: I was expecting to be bowled over. I went twice and neither time did I feel impressed by the beer. There was some quality that I can't define but know very well (if it helps, it's that taste that differentiates a Molson Canadian/Labatt's Blue from a Bud or Miller). If I were a real beer guy, I'm sure I could give you the official term. One of my friends complained about a lack of hops in most of the beer, but I'm not completely sold that this was my issue - could it be that the hops are simply different from west coast (US) hops? In any case, my west coast IPA/German hefeweizen/Belgian white ale sensibilities were not that excited.
St. Ambroise: I had previously really enjoyed SA pale ale, but this time I thought it was OK but not terrific.
Unibroue: I normally quite like Blanche de Chambly, and the pint I had from a presumably fresher batch on tap was even better than normal. I really liked this one. I'm now kicking myself for not having Fin du Monde on tap.
Reservoir: didn't much like their beers. Even less interesting than Dieu du Ciel.
Where I wish I'd tried: I wish I'd gone to the other branches of the Joe Beef empire, particularly McKiernan (which is now open for dinner on Wednesdays). Struck me as the sort of place I'd frequent if I were a local. Heard lots of good things about Garde Manger and Ferreira; I'll try to hit them up next time. Cremerie Meu Meu sounded great, as did Vices&Versa.
That's it for the food section. An aside for visitors on getting around:
There's a huge system of automated rental bicycle stations called Bixi (bixi.com). It is a really cool system and it was perfect for moving around in central Montreal. It's an excellent concept whose implementation needs a few refinements. Basically, bike rentals are $5 per day fixed rate for as many trips as you want, provided that each trip is LESS than 30 min long. If you keep a single bike for longer than 30 min, then additional charges apply. You must wait for 5 min before grabbing another bike. The idea is obviously to keep bikes turning over, so you go to one neighborhood via Bixi and drop off your bike, then do a one or more errands, then grab another bike and head to your next destination. It's not useful for touring the city (or rather, it gets much more expensive if you use it this way). But going to grab bagels for breakfast when you are staying downtown? Going for dinner in Mile End? Perfect! The bikes even come with lights so you can use them after dark. Plus, Montreal has a pretty great system of bike lanes and cars were generally extremely courteous towards cyclists. I found it to be an amazingly useful system for tourists. The two warnings I'd give is that, first, while there are tons of Bixi stations (you're rarely more than 2 or 3 blocks from one) around, they're not always the easiest to spot so make sure you have a destination station in mind before you leave (or maybe one can get a Bixi map somehow, but I didn't stop in to ask at tourist information). Secondly, and the thing they need to improve: some stations and/or some bike slots within a station don't function. This means you either can't get a bike out of that slot (or all slots at a station) or you can't return your bike to an empty slot. Sometimes some slots in one station worked so you had to trial and error it. Sometimes the whole station was cursed (or, more likely, lacking power for whatever reason). This necessitated finding an alternate return station maybe a 20 to 25% of the time, which was a nuisance for sure, but overall I was very impressed. I used the Metro once and it was quite user friendly as well, but at $2.75 per ticket it would clearly be more expensive than Bixi, plus you don't get to explore the city and work off some of the food adventures.