anjohl: It's all rather moot though, since who cares if there are DRM's in games you are essentially renting? That and the fact that Steam is a DRM. The only logical reason I can see a Steam user complaining about DRM's is regarding SecuRom, since apparently its notoriously impossible to remove from your machine once it's on there, and it takes Higher-than-admin level priviledge.
Even though Steam is a form of DRM, it does not limit your installs or anything like that... there is no reason to worry about a Steam game running and working as long as Steam still exists, and even after. One of the great benefits of Steam, when not hampered by outside DRM, is that you can install it and all your games anywhere you want, on any computer you want.
SecuROM games with activation limits on the other hand... not so much. 5 machines/reformats later and you have no game unless you beg for another install. Usually you only get one more, maybe two. After that Steam won't even let you buy another copy, since you already did, you have to buy one from somewhere else (or pirate it, since you would be morally justified in doing so for obvious reasons).
There is a HUGE difference.