I first disclaim any expertise beyond knowing what I like :)
Cordavi: We had truly excellent food and it was a real bargain. My seared foie gras was perfect, my "truffle infused" tenderloin was among the best steaks I have ever had in my life, my wife loved her butter poached lobster, the cheese course (no cart or choices) was excellent with each of the four cheeses having something nice to go with them (almonds, figs, etc.). Wine list quite limited. They sat us (with a reservation) downstairs at a table in the bar. It got obnoxiously loud toward the end. The next time I would insist on sitting upstairs. I would definitely go back--the food was great.
Marina Variety Store Restaurant: Fabulous breakfast. My shrimp and grits was perfect and my wife's side of fried oysters was delicious. They made a mistake with the order, however, and brought me a side of fried oysters too. When I told the waiter, he merely said: "Happy New Year." The oysters were great. I would have breakfast here every day the next time I come to Charleston, except I would want Poogan's Porch biscuits described below.
Poogan's Porch: We went for breakfast because a post here said they made a great biscuit. And indeed, it might have been the best restaurant biscuit I have ever had. My wife's shrimp and grits were great. My she-crab soup was not very good. I would go back for the biscuits though.
Cafe Cru: Very nice. I had a fried oyster salad (anyone noticing a theme) that was wonderful along with some good mussels. I can't remember what my wife had but she loved it. Someone's (?the chef's) grandmother made the dessert, "Huguenot Cake," and it was sublime.
McCrady's: We went for New Year's Eve. I thought the food was terrible, it stands out in my mind as one of the worst "fancy" restaurant meals I have ever had. The foie gras didn't taste good (words I thought myself incapable of writing), the sweetbreads were in cubes and just not good, the grouper was tasty but overcooked, and the venison tasted ok but looked very unappetizing on the plate. For $105 per person (and a mystery charge of $32 for "bar sweetbreads" which they removed) it was a minor tragedy. I would not go back even for a free meal.
Home Team Barbeque (Ashley River Road): On the way back from Magnolia Plantations I noticed a neon sign of a pig. I'm always attracted to flashing pigs, so we went in. The barbeque sandwich was good and cheap. I wouldn't go out of my way but was happy I went.
In Transit from Savannah to Charleston:
Sweatman's: Very very very glad I went. First of all, very easy to find (only open Friday and Saturday lunch and dinner, no phone). All you can eat (as many times through the line as you want.) Between 8 and 9 dollars which includes tea, and an extra .65 for banana pudding. The hash which I guess is essentially essence of pig in liquid form (but I can't be certain) which I had over rice was divine. I would go back just for that. I've never had anything like it. The pig meat was wonderfully flavorful, especially the dark. You can get two kinds of sauce but after tasting it (it was fine) I ignored it, because the meat was so good. They have a sign: "We Don't Guarantee Skin!" but they had it when I was there and it was great. The ribs were great too. It's less than one hour from Charleston. I would drive at least two. I can't emphasize how much I enjoyed it.
Bistro Savannah: Average. My wife liked it.
Johnny Harris Restaurant: We went twice. I am sure many would say nothing special, but the dining room (I guess 70 or so years old) is a great room and a great place to eat. I had the barbeque twice and while it ain't Sweatman's (what is), I liked it. My wife had fried chicken (it had no batter) and it was very good. I would go back.
Mrs. Wilkes Dining Room: My wife wanted to go. We stood in line about 20 minutes. It's family style and they seat you with strangers at a table for 8 or so--they bring about five main dishes and ten sides. It cost about $15. The fried chicken was superb. I would return for that (but I wouldn't stand in line for much more time than I did). The barbeque was quite good. Many of the sides were quite nice. All in all, it was better than I expected it would be.
Old Timey Town BBQ--Good ribs, very strange atmosphere.