tfishell: Steam is not DRM, similar to how GOG is not DRM, they're both digital distributors. But the fact that Steam
forces a client on you could be considered DRM, obviously.
Nirth: I thought CEG is the reason Steam is considered DRM. The client itself is only a distribution channel, similar to how when people download installer files through HTTP at GOG. Granted, you get an installer and not "installed" files but if the game works with the latter that's not the important issue. The issue with Steam falls back to CEG, they encrypt the .EXE-files. Without that you can play the game without the client (like with Desura).
It seems to be rather vague. I think a lot of GOG's "old-timey" members here believe only CEG is DRM, whereas, perhaps, some of the newer members who only know of "Steam = DRM!" think the client in and of itself is DRM.
Part of the problem is the lack of communication: you don't hear Steam tell people many games are actually DRM-free and can be played directly from the .EXE, possibly because they don't want to upset publishers by letting people know they
can put these files up for pirates (or something like that). Likewise, I don't think GOG has really ever said, "Well, technically Steam has DRM-free games," because they know that could hurt their brand.
I won't buy on Steam anymore because I'm interested in helping the competition who can give Steam a run for its money, ie GOG (although that enthusiasm comes and goes admittedly); for example, the Humongous games - I won't buy them until installer files are released from some service.