Decent crab cake at Rams Head and then there are the chains. Fogo, McMcormick's, all the standard steak joints are around the harbor.
Charleston is great, but spendy. Oceanaire is always good, as is Roy's. If you want to head a few miles north check out
Woodberry Kitchen: Celebrating the Traditions and Ingredients of the Chesapeake Region , good food but get a reservation now.
Let me know if you have something specific in mind.