I still rely on Windows for a few important things (namely a Club Penguin Singleplayer Client that I'm not sure works on Linux), but I absolutely will switch to Linux as soon as I'm fully ready to take the leap.
Debian seems like a nice distro (am I the only one who calls it "deebian"?)
I heard Houdini has a Linux version. I might try that out, especially since it does have ActionScript 3 support (which Club Penguin started using in 2011)