Negril is really cool! Just remember that the locals are friendly because they want to SELL you something. Whether that something is worthwhile or even legal or not isn't the point. They are VERY PUSHY salespeople. It can be a turnoff but once you get used to the idea that by being American in their country that they know you have a couple of extra dollars in your pocket that they'd like to get their hands on, you will be fine.
The advice I got from the person who drove me to the cottage:
1) This isn't your first time in country. You've been coming here for 10 years now. They will immediately back off a little.
2) Don't go too far west on the beach until you are comfortable with the surroundings. The further west, the more sketchy it becomes to Americans. Once you are used to it, then go shopping! My wife, daughter and I had a blast going to see all the different beach retail stops once I realized that the locals knew I was going to buy what I WANTED. Once they realized that they couldn't "sell me" they weren't quite so pushy and left us alone.
Americans aren't used to the hard sell... They use it because it works on us. We, generally, have a difficult time telling people NO, to their face. It makes Jamaicans SEEM dangerous.
Learn the power of NO and be generally cautious. You will have a great time there. If you are afraid of strangers and people that don't look/act like you, then you probably aren't quite ready for it. Not yet at least.
[This message has been edited by Say Chowdah (edited 11/22/2009 3:39p).]