Calorie Counter Device - Help!

I’m in the market to buy a calorie counter watch but I have no clue on which on to get with so many out there. Does any one have any suggestions on which one to get or to NOT get? What other features should I look for in shopping for these? I want something as accurate as possible when it comes to calories being burned. (Something reasonably priced would be nice!)
What should I get?
Thanks! =)