A friend turned me on to Green Man Gaming recently. They have some pretty good deals on a wide range of games (some of which activate on Steam). One of the biggest attractions for me is, they have a trade-in policy. Right now, they offer trade in for console games only in the UK (they're looking to expand to other countries soon). However, they also have a program for trading in your digital games as well. I'm definitely intrigued, and may toss some business their way.