All good suggestions Note that in FLL staying at one of the places in the gay enclave will make it easy to make friends, but you need a car to go further than the beach or the Galleria. Cabs can rack up quick unless you are lucky enough to hook up with a buddy to go places with.
Unfortunately, it will be a bit difficult to hook up with your age group in most US destinations. The Euro younger crowd travels more than us Yanks, which is why I'd recommend BCN or someplace like that if you can swing it.