Eh?

All the single player games that don't require an internet connection can be played in Steam offline.

Simply make sure Steam is not running, disconnect from the internet and run Steam. It will tell you that it can't connect and give you the option of starting in offline mode. Run your game and off you go, simple and easy.

Steam platform is today more a DRM platform that an online distribution systen. Steam on my PC has several issues that prevents game to be launched because of strange failed validations or valve servers unavailable and many times I have to reset Steam to be able to play.
I think that all these issues depend on DRM.
Forced updates also create problems at LAN parties because some players do not have the last minute update.

Furtermore :
- You cannot sell or give your games to other persons.
- Games prices on Steam are many times higher than retail DVD.

So I decided to limit Steam to the Valve games only. DVD's DRM causes less troubles and can (hoping) be removed by uninstalling the game.

Valve wants install limits they are sick of people re-downloading 9-10gb a of data to each of their comptuters, imagine 100,000 people downloading the game content multiple times it is very bandwidth costly and their paying for this.

being able to copy the setup/run files between pc's soon mark my words valve will stop you downloading from their servers they will expect you to download once burn to a disc or discs, and then when you want to re-install to another PC you have the disc.

they will then defend themselves by saying you have un-drm'd game files where we want you to burn copy to other pc's thus not allowing you to keep downloading game files from their service..

be warned it's coming

I'm a DRM hater like most, i was really interested in spore untill i heard what a s*** of a DRM it has. Never bought it. But yet if this is as you say, being that i use steam and have my own account. I can realy say i cant see a problem with it, i buy games off steam just like a great many others and i cant see the issue with this if it's at simple as it sounds.

Although in my view i dont think valve need DRM anyhow, i expect they are just doing it to tick a few boxes to get more game developers to use their platform, which is always good for everyone.