Hi,

I only want to point out, that Gamersgate removed the DRM from S.T.A.L.K.E.R. Clear Sky.

http://www.gamersgate.com/DD-STALKERCS/stalker-clear-sky

I hope that GOG will bring the S.T.A.L.K.E.R. series soon.

People always forget the other essential component of GOG releases. I followed your link and...
"This product is not available for purchase from your location."

Not only they need to convince or wait on the publisher to remove DRM, they need worldwide distribution rights.

Could be worse. Skyrim I bought from GG wasn't marked as such, but didn't activate here. Had to get a refund.

I'm from Germany but the link should als work worldwide ... except UK.
Then you have to go to:
http://www.gamersgate.co.uk/DD-STALKERCS/stalker-clear-sky
If not, then it's not difficult to use a VPN. Hotspot Shield should do the trick. That's also the way to buy uncut games in Germany. ;)