First off, the published weight on bars is all over the place. I've seen actual weight being more than 20-30% different than the published weight. This is also due to the fact some manufacturers weight the 42cm version (pretty standard) of their bars, while other only weight the "short and shallow" 40cm version. So the difference you see may not be the actual difference.

The ones I normally would go for are 3T and Zipp because they fit me well. Ritchey, Easton and ENVE are obviously reputable makers of carbon bars, and so is Thomson and Fizik. One thing to note, for carbon bars, I would be very cognizant of the counterfeit ones on eBay and on the web. They seem to be pretty rampant.