I'd recommend that you look into Ubuntulinux
http://www.ubuntu.com/
I don't think you'll be disappointed... I use it as my main OS and I really like it. I'm guessing that if you're willing to switch to OS X you would be willing to switch to Ubuntu. You won't be disappointed with the desktop effects either... it's really cool.

The only thing I don't like is the graphics (icons wallpaper and the theme), but that can be changed VERY easily so it's not a big deal.