Here's my take on going completely non-Microsoft at home.
1. Running Linux or any flavor of BSD is not a problem.
2. My email is based off an HTML browser or SMTP, I can use many, many applications to send/receive mail.
3. Most applications that I use have *nix counterpart. That includes watching .mpgs, .avi's; listening to .mp3's, etc.
The ONLY reason why I don't run a non Microsoft OS on a 24/7 basis is the fact that I play lots of games on my PC. If I were to go solely without games, I could run Linux pretty much without any hassles. Don't get me wrong, I can play a handful of games and mods under Linux, but I cannot play games such as Max Payne, Operation Flashpoint, Half-Life and many other titles. Most titles available today are for Win32, so that's why I stick to Win32 for the time being.
There are movements, specifically distributions, geared toward bringing gaming to Linux "without" an emulation layer. If I could play over 85% of the Win32 titles under Linux, at full acceleration, with minimal to no patching, I would switch in a blink. That day has yet to come, but when it does, I'll post my results here.
vash