Himarshee St. (2nd street) in Downtown Ft Lauderdale is a good place to check out.. Live bands in the clubs/bars up and down this street. You can walk around with your drinks and most places don't charge a cover. Most places are open til at least 4am on the weekends.
About 5 minutes walking from there is a riverfront district with a bunch of bars , restaurants, and shops, live jazz music, and huge yachts parked on the New River.
Las Olas is cool for a more laid back, but snobby environment, with boutiques and shit like that.
Beach place is about 10 minutes driving from there, with a couple clubs, shops, etc.
and south beach is about an hour driving from Ft. Lauderdale, and there are plenty of places down there.