Thanks for all the suggestions guys -- here are the results.
The Palms for lunch -- ghastly: mall food court atmosphere, poor quality food. I couldn't find a dessert that was edible.
On the other hand, thanks for the tip about the Aladdin buffet. I pushed my friend, who said she had heard mixed reviews. I don't know if the meal we had was typical, since it was their New Year's Day brunch menu ($16.99), but the quality of the food and preparation was excellent -- about as good as you can get for this kind of mass food service operation. Wide spectrum of foods offered in ethnic stations (Mexican, Middle Eastern, American, Italian, Asian) plus soup, salad, dessert and seafood, also champagne (with fresh-squeezed OJ for Mimosas) and Bloody Marys.
I was particularly impressed by the strip loin roast they were offering instead of prime rib (an improvement in my book). It was flavorful and so tender I could actually cut my half-inch thick slab with a fork, while not being mushy or overly fatty. If they have it, don't miss the star of the dessert offerings: crepes topped with warm peaches in brown sugar sauce and then drizzled with raspberry sauce. The peaches were either fresh or frozen, not canned, so they had a firm texture, and the crepes turned out to be filled with a small amount of melted dark chocolate. Delicious!
Other items that showed off the quality of the kitchen: tandoori chicken that was juicy and flavorful, not dried out; brussels sprouts sauteed with onions and bacon that were al dente, not soggy and "cabbagy"; and Southeast Asian style spring rolls that were delicate and crunchy, not soggy, greasy, over-crisped, tough, etc. I was also impressed that the watermelon actually had flavor, rare in the off-season. Someone is making an effort to buy good ingredients, and the kitchen knows what to do with them.
Otherwise, I had a surprisingly decent meal at Woolihan's Pub in the Marriot/Regent. Even though it's in a casino, there are a lot of locals who hang out there for the live music (no cover, no minimum, at least not on a Monday)and to do a little impromptu Irish step dancing. The special chicken I had was good, the roasted potatoes that came with it were perfect, and the warm plum cake with sticky toffee sauce was "to die for." My friend thought it was overpriced, but I thought it was quite reasonable (most entrees under $10, desserts under $4).
We also had lunch at the new Bergin Baking Co. -- off the strip way out West Sahara, owned by a woman who was the head pastry chef at Spago's for years. A breakfast/lunch place with a bakery counter. Creative menu -- light but flavorful (I had a Mediterranean tuna salad made without mayo and with capers, green olives, etc.). The baked goods are European style -- not overly sweet or heavily iced. The breakfast offerings looked yummy, and I think if I lived in town I'd find myself stopping in for a pastry and some tea on a regular basis. I thought the prices were reasonable (but then, I'm from the SF Bay Area -- the prices almost everywhere in Las Vegas look reasonable). 7365 W. Sahara Ave. 5:30 a.m.-5 p.m. daily.
A place I'd like to try is the Caspian Market Restaurant (2101 S Decatur Blvd., in the Trader Joe's Plaza). We just popped in on the market side to get some snacks (honey almond pistachio brittle, fresh halvah), but the food smelled great. Although the owner appears to be Armenian, the food is billed as Middle Eastern and Persian. Actually, there's a lot of good ethnic eating in Las Vegas -- we didn't get to the Colombian place she wanted to take me, for example.
And of course, Lotus of Siam. Be sure to say you read about it on chowhound -- at which point the other menu appears. Everything was good, and the rice with sour sausage was revelatory. You can get food that isn't too hot, but you really need to emphasize that you want no more than a three. Some of the dishes on the northern menu are not hot at all, so plunge in.
In short, there are lots of good eats in Vegas, off the Strip as well as on.