Paingiver: I looked to GamersGate but it seems if you buy from them you can only install from internet? Isn't there a site like GOG?
Officially, GamersGate requires an internet authentication each time you install a game, in order to decrypt the installer. Practically, you need to do the authentication only once - just copy the decrypted installer out of the folder before it gets encrypted again. You then never need to authenticate this game again. You don't even need to actually install the game to do this, it's enough to just start the installation. So, for every game I buy at GamersGate, I decrypt the installer using this method, and then burn the files on a DVD, as a fully functioning archive that doesn't need online authentication ever again. Which is good enough for me - as long as that's possible, I'll keep buying there.