There's a Kickstarter project for a new website called The Brick Stop. It will be a place for members to buy, sell and trade Lego. They're trying to improve on some of the outdated and clunky sites out there, and to streamline the process for both sellers and buyers. Also, there will be no seller fees.
I found out about it on Brickset and I'm pretty excited about the idea. Read more on the project's Kickstarter page: http://www.kickstarter.com/projects/1401652493/the-ultimate-website-to-trade-lego-bricks-and-inst