Seconding a few previously-mentioned nominations, and adding some expansions.
Circa 1886 is behind the Wentworth House/Mansion, and it’s very classy, and pretty pricey. It is the epitome of old Charleston money. Dress business nice for breakfast/lunch, church clothes for dinner. They have the absolute best shrimp and grits that I have ever eaten in my life, and everything else we ate there was delightful. My husband and I stayed at Wentworth, with Circa meals included, for our honeymoon, and we’re currently saving up for another stay for our 10th anniversary.
I’m with **skylyn **- Savannah really has a better rep for seafood, but there’s still plenty of good places.
Charleston Crab House is probably your best bet for “traditional” seafood. Lots of fried stuff, oysters, shrimp by the pound, all that. Not too expensive, LOTS of food.
I’ve heard good things about Tommy Condons, but I’ve never been myself.
SNOB is good, but nothing especially memorable.
High Cotton is newer, and they’re excellent. I’ve eaten at the Charleston one and the Greenville one, and had no complaints whatsoever.
Sticky Fingers is good, but they’re not consistent. Sometimes the ribs are aaaaamaaaaazing, and sometimes they’re just - eh, decent ribs tonight. Never bad, but not always the top of their game.
TBonz is very like Sticky Fingers, but with more of a steak angle. I find them more consistent than Sticky Fingers, but I also like steaks more than ribs. They’ve got an unfair advantage in that they’re literally connected to ----
Kaminskys, which you really ought to visit for dessert. They’ve got a rotating cake/pie selection that is full of amazingness, and they make homemade milkshakes and have a huge selection of drinks, alcoholic and not. You can eat there, or take a slice to go, but you can’t take the drinks outside, so if you want a nice mint milkshake made with a shot of Rumplemintz liqueur, you’ve got to wait for a table.
Finally, a duo of lower-class Charleston staples: If you want a cheap lunch break, or want to hit the less-fancy side of life, try out these two:
Andolinis Pizza. There’s at least one downtown close to the Wentworth, and there are more scattered around the region: one on James Island, one in West Ashley, probably one over the bridge heading towards Daniels Island. All the places are dives, but huge slices, made fresh, and lots of fun.
Ye Ole Fashioned Cafe and Ice Cream isn’t actually in the city - you’ll have to head over the bridge towards James Island/Savannah Hwy, but it’s cute, it’s been part of the landscape pretty much forever, and if you want a good classic “diner/cafe” sandwich and shake, it’s great.