Having recently made the leap to Linux in April as my only computing OS, and wanting games to work on it, I deliberately went with Nvidia as my GPU, which has historically had better support from the Linux community than AMD processors.
It's not just for the sake of gaming, since I do graphic art as well as gaming, so I needed a GPU that wouldn't be bothering me every time I spun up a program.
Intel GPU's as discrete video cards (as opposed to integrated with the CPU or a chip on the MB) is relatively new. Worse, Intel processors and boards are still more expensive (at least they were in April) than AMD's offerings, even when not riding the bleeding edge.
Nvidia's GPU's were more expensive than AMD's, though, but I figured the extra cost up front would pay for itself in fewer headaches down the road. So far, that's played out.
It's nice to see Linux being taken seriously as a gaming platform, too, which wasn't a huge consideration when I made the switch. I've installed Steam on it, and do have some games I bought through them that I could install, but I hadn't played them in years, so I'm not in any great rush to try them out. Still, the games I HAVE installed were not hard to install (though harder than in Windows), and they play with very few, if any, noticeable issues.
It's not an OS for everyone, but if you're looking for something that isn't Microsoft or Apple, and still want to be able to do what you did before, odds are pretty good you can get all your stuff to work in Linux, including games.
