I think there's no question that gamers would flock to Linux if A) it were easy to install, use, and maintain, and B) Windows games could be made to run in it.
Fortunately, both of these conditions are pretty well fulfilled right now with Ubuntu and Wine, and this will only be getting better. I can run most of the Windows games I want to under Ubuntu/Wine with just a little work (generally no more than is required to pirate a game--a process thousands of gamers appear to have mastered), and the ones I can't run well presently generally become playable over time as the codeheads come up with solutions and Wine itself is improved (which it is currently being, by leaps and bounds).
In return for a little extra work on the gaming front, I get a stable, secure, and free OS, tons of free software comparable in quality to what I used to pay hundreds of dollars for, and freedom from the whole virtual monopoly that is the Microsoft world. (What software isn't available natively can almost always be made to run under Wine, just like the games can.) As for customer support, I get quicker, more helpful answers from the Ubuntu boards than I ever got from a major software company.
Honestly, I read some of the comments here and wonder what planet these people are living on. I'm doing the Linux gaming thing RIGHT NOW and there's exactly zero chance, barring some unforeseen calamity, that I'll ever be going back to Windows. I give it a couple of years before the scales fall from the eyes of the masses and they begin to follow in droves. If the company behind Ubuntu wasn't a private concern, I would have already poured every penny I own into their stock.