I've been twice, and actually enjoyed it quite alot. x2 on PT's Hedonism suggestion... All inclusive, adults only, and stuff to do.
If you venture out, it's not as bad as people make it out to be. I've done the resort thing, and the rent a hotel / house thing...
For the first time, a resort (Hedonism) and organized tours might be the way to go. If you do tours, I suggest an independent like Marzouca (
http://www.marzouca.com/ or
http://jamaicajump.com/ ) as opposed to through a resort.
I liked Negril, but that's me. I'd like to experience Kingston, but maybe not as a full destination.
It really depends what you want. If you are the type that would backpack through Europe, get a hotel in some city and figure it out as you go, or take an expedition through a 3rd world country, you'll could enjoy the non-resort areas of Jamaica.
If you like organized tours, nice hotels, cruises, and no risk... Jamaica can offer that in a resort... but there are better places to just lay on the beach and drink stuff with umbrellas in it.
Jamaica is very economically depressed, and rough around the edges, but in general, the people are super nice as a whole... but they can and will take advantage of clueless tourists.