The FLGSs of note in Greenville, South Carolina are as follows:
Boardwalk & Park Place: Located in the Haywood Mall, it's a Harry Potter-esque store, packed wall-to-wall with all conceivable games. If you wend your way through the close-packed stacks of Go games and expansion sets for "Apples to Apples" (an excellent party-oriented card game, by the way) you come to the Back Wall, where there exist a plethora of RPG books. About 60% is dedicated to d20 material (from WotC Core Rulebooks to the Book of Erotic Fantasy), and the rest is other games (Call of Cthulhu, Battletech, Vampire, etc). This store has a variety of products from WotC, AEG, FFG, Green Ronin, etc.
Borderlands: Located on Laurens Road not too far from my favorite tobacconist and around the corner from a great Indian restaurant. This is your typical FLGS, with wargame tables in back and a large collection of miniatures, paints, and terrains. Lots of good D&D stuff here, though not much non-d20 stuff. Also a good collection of comic books, too. Importantly, the owner is an amazing guy who will go out of his way to order something for you. My wife is a gaming-dice-freak, and she'll ask this guy to order something that's been out of circulation for awhile, and he'll still locate one for her! Awesome!
Haven Games: A hole-in-the-wall shop on Woodruff Road, not too far from where I live. Their selection is tiny, and all WotC-only. If I can't find a Forgotten Realms book anywhere else, I can be reasonably sure it's here. The place is tiny. There are a couple gaming tables in the back of the store, but they really don't fit. Did I mention the place is tiny? Employees seem to have limited knowledge of -- well, the world around them.
All-in-all, Borderlands is my favorite, though the owner of Boardwalk & Park Place is a nice guy who's always opening a new game to get customers to try. If he's working, I make sure to stop in and see what new game he's playing with on that particular day.