I like to advocate Impulse. It's DRM-free and lets you play games without having to run it in the background. This also means that you can run the same game at multiple places, at the same time.
I've decided to make all digital purchases off Impulse from now on, unless it requires Steam to run in the background (like Civilization 5 or Empire: Total War). The pricing tends to be the same or similar. Just got Company of Heroes: Gold for $14.99 off Impulse this Thanksgiving Break.
But Steam is alright. I abhor the lack of profiles for games and the lack of running a game in multiple places at the same time, however.
- Former Star Wars: Jedi Knight: Jedi Academy, Star Wars: Battlefront, and Star Wars: Battlefront II modder. Used to go by the name "Majin Revan."