junkeymonkey :
and be ready to hack at the terminal to do what a simple install on windows would be
This appears to be a misconception most people have who do not use Ubuntu, or any other Linux distro. I use Ubuntu regularly for productivity and whilst you can use the terminal for pretty much everything, and a lot of the time using the terminal simplifies these tasks, the GUI is just as capable as Windows. You can also install Steam on Linux and there are quite a lot of games that run on Linux natively (the number of games is also rising rapidly with the release of Linux-based Steam OS). Check out
this link for a list of Linux games on Steam.
However, overall I would still say gaming is best on Windows 7 (and 8) for the time being as you have the guarantee that if a game is coming out on PC it will be available on the Windows platform and as
this video shows games perform better on average on Windows (due to more consistent driver updates).