I'll vouch for some already mentioned shops: Nocturnal in Philly and No-Comply in Austin. Both great places with good people, No-Comply especially. Tons of stuff available, friendly dudes, and a great park right behind the shop.
I'll add: Delicious Skateshop in Wake Forest, North Carolina. The shop itself had an ok selection, but the two-story park inside sealed the deal. There's a concrete bowl setup outside too.
Civil in Providence, Rhode Island. They have a few locations but I only scoped Providence. Tons of product, cool dudes. Decent proximity to NJ and New York if you want to go down the east-coast.
Warped Sportz in Crown Point, Indiana. There's really no reason I'd imagine anyone visiting, but if you're in the area check it out... it's all we have haha. Great place though.