1) All of the linux distro are good in there own way.
http://www.zegeniestudios.net/ldc/ is a quiz that tells you which distro is best suit for you.
2)
www.linuxgames.com/ is a great site that has linux games
3) The platform for the PC games are usually windows, so NO you can't play windows games. LIke geese said there are emulators, so it could work. But the majority of the time it crash (on me).
4) Yes you can, I try that once with one of my friend (I had linux and he had windows)
If your a heavy gamer, I suggest you use windows, only because all the good games and be mutli - played, while for linux only a handful can "intercross" with a windows computer.