I think st aug is a really cool old city. Hooked on Harrys has good food and A1A has good beers. It's very touristy, so you should find plenty to do. The fort, cathedral, and lighthouse are interesting if you're into history. The nightlife is hit or miss - the place is littered with bars that will either be hopping or completely dead. But with 30 of you, you can make you're own party.