I haven't used Steam, but I am becoming a fan of the relatively new Gamersgate (http://www.gamersgate.com/ http://www.gamersgate.com/). It doesn't even require

I haven't used Steam, but I am becoming a fan of the relatively new Gamersgate (http://www.gamersgate.com/ http://www.gamersgate.com/). It doesn't even require a desktop client, which is one of the few complaints I've heard about Steam. However, none of the games I've purchased there use DRM at all, so I don't know for sure how DRM games work with it.