Cape Town, S.A - absolutely beautiful and the ppl there are really friendly. Also, the exchange rate is amazingly in your favour at the moment so things there are even cheaper than usual. I go there every xmas - been going for 12yrs now.
Paradise Island - the name sums it up really. It's near Nassau, but much smaller and less touristy.
Atlantis is always a good choice too actually, especially if you like more active holidays.
Marbella, Spain - sun, sea sand ... the best seafood ever, good nightlife, loads of young people. And the town has had a load spent on it over the last few years so it's now really beautiful and has lost the tackiness it used to be associated with.
Majorca or Ibiza - where you stay there depends on what you're looking for. Both of the islands have areas full of huge clubs, all night parties and drunken, sex-crazed students tripping their tits off ... but there's also more secluded spots on the other side of the islands where you can dine out at cozy little seaview restaurants, sunbathe on beaches that are completely isolated save for yourself and do the 'romantic cultural' thing.
I haven't been but Barbadoes is somewhere I've always wanted to go too. Ppl I know who have been always say it's incredible.