While the current version of Ubuntu is trashed by many, its usability is no longer an issue---as near as I can tell the argument is what it looks like with a few quibbles over changes to some standard utilities---the app installer used to allow you to check off the ones you wanted and then install all at once. No longer (or if it does, it is cleverly hidden!) I'd suggest if a user has problems with this particular flavor of Linux, then their chances of success with Win7 or Win8 seem unlikely.
Definitely. As I mentioned, I installed Ubuntu on my roommates laptop. He is completely inexperienced in computers, and not only has he had no problems with Ubuntu, but he has also become more productive than when he was on Windows 7.
(long time linux user, also Microsoft employee. I take credit for the joke, though :P)
[edit: I know there are games for linux. In fact, I applaud companies that go out of their way to make linux versions of their games. e.g. Unreal Tournament 2k4]
Hah, you do have a point though--even if there are great games for Linux, most of the popular ones (at least for my demographic ;) are Windows-only, and gaming is as much about playing with friends as it is about the quality of the games.
However, my roommate, like a bunch of my other friends, is entirely an XBox person, so the games aren't the issue.
While you have a point - many games are Windows only - I think it has more to do with focusing on the work rather than on the tool. Windows is intrusive. Ubuntu, much like OSX allow me to just let it flow.
On my case, Ubuntu has an edge because it resembles my servers more closely.