A nice place, although I almost went off my head after staying there for 3 months (it was for work though, mostly) I stayed in the north end of the island near grande baie, which has a few good pubs and clubs. Try the Banana Bar for a good atmosphere, then the nightclub joined called Zanzibar - Wed nights usually involve buckets of water, or was it just us? A wee bit touristy but a good time all the same, an very large pena colada.
Diving a definate if you can fit it in the budget, recomend angelo diving in grande baie, i had great 1 on 1 training from the french guy 'Fred' - say hello to him from the Kiwi guy who was there filming if you do.