Copy protections are getting worse and worse (someone read about the Ubisoft debacle?), but Steam is running really really good and offers some nice features. I think most Windows gamers will agree that as long as Valve is controlling Steam, you're good to go.
I wonder what kind of exit strategy Valve has if they ever have to close the doors of Steam. Will they put all games in "offline mode", so you don't depend on the Steam servers anymore?