gaming wise yea we all know the answer when it comes to linux. But, with Steam going over to Mac's, i'm hoping and thinking that Steam may do the same and eventually work on linux. If that ever happens and they actually get their games to run i may look into linux as TF2, L4D, CSS are bout all i play nowadays.
There is a working version of steam on Linux, however, it is not public
I don't think Valve is going to push linux until the GPU manufacturers pull their head out of their asses with GPU drivers on Linux, and get some decent support, and good API's going.
Of which wont happen until linux becomes important enough..... Being on OS X however, makes the porting process significantly easier, and hopefully the Linux community will adopt Apple's OpenCL approaches. It may provide the boost Linux needs.
Compiz works great on Mint out of the box tho, and ive noticed the proprietary driver installer for uBuntu has made GREAT strides. Out of the box, Catalyst control center on my Thinkpad x100e.