I like lubuntu
it's been easy enough to use, considering its a free unix system.
ubuntu is fairly mainstream
it runs fine on the laptop I bought in 2004, as does XP (with no service packs or virus protection)
it hardly uses any system resources, leaving more for games
steam for linux beta is out, thus far it runs smooth as silk, (only tested Solar2 atm)
Connected to my TV it runs anime (via VLC) better than the TV, as good as Win7.
Getting the OS running is a simmilar hassle to setting up windows (no flash/Java/Firefox for example)
I installed a copy on a 16GB USB, it runs fine and now I can exclude the OS from any PC issues I have in the future.
doesnt nag me about openning files. occasionally asks for a password but no nearly as annoying as windows.
It's not mainstream, just like my trackball mouse.
Using it sort of reminds me of playing Space Rangers 2, one of the best UI's I have seen in a game and it also had ~3 fully integrated minigames.
ubuntu had an app market before there was such a thing and its still really easy to find and install programs with it.
For me the OS should have as small a footprint as possible leaving me plenty of power to get <100 ping and 60FPS in LOL and GW2 (for example). Thus I think Lubuntu is better for gaming that Win7, the only think holding me back is compatibility with games being built nearly exclusively for windows.
Seems to me my broken/slow/old PC BYO will now be my new media center. Plugged into the TV for watching anime/YouTube and running the occasionall game over Steam. Pretty keen to trial Psyconaughts in BigScreen mode with a controller and pretending I am a console gamer. I suppose I need a new wireless keyboard+trackball mouse for all other games though and to press "V", "B" & " " in VLC.