I'd also go with the Ubuntu version. It's an older version as far as I can see (Gutsy Gibbon - 3 version behind the latest PC version), but then I'm still running the even earlier Feisty Fawn without any problems. From my experience, Linux is really easy to use once you've learnt how to use it. But it's a pain learning stuff! I find it harder to muddle by on Linux than on Windows.
The graphics chip isn't available in Linux, so it won't be much good for recent games (I doubt Cell alone has the power to emulate PS2 - maybe PS1).