I very rarely play games outside of Steam. I try to purchase everything I can on Steam. I have an original copy of The Witcher, an Enhanced Edition copy, and I STILL keep thinking about ordering it on Steam.
Now I have an even bigger reason.
Steam is getting another upgrade this week called "Steam Cloud". This will allow user saves and configurations to be stored on Valve's servers. Like the games you buy on Steam, this will allow you to download and have access to your configurations for CS:S, Half-Life 2, etc. ANYWHERE.
I can only hope and pray that it extends to all games on Steam because I install and uninstall games at a compulsive rate. Painkiller is a game that sees bi-monthly installs. I'll play it for two weeks, kill as many guys as I feel the need to, then get rid of it. S.T.A.L.K.E.R.: SoC on the other hand has been sitting on my computer for months now. I'm afraid to uninstall it because I will lose my saves. Now, I won't have to sorry about it. If this is something that will only extent to Valve games, which I can understand, I'll be a bit disappointed. I just means that S.T.A.L.K.E.R. and Hitman still won't see uninstall.
"Sauce"age
But I agree: Steam Cloud is awesome.
Don't get your hopes up for third party support, not from the bigger developers/publishers at least.
Damn, that's a shame. Considering third party companies keep putting DRM on their games on Steam, I guess it was thinking too brightly they would take something like this up.