You can get most games to play in Linux, but expect it to be a pain in the *ss. WINE will do a lot of them, but you may need to get Cedega. As far as everything else, install OpenOffice, and you should have no trouble ditching Windows. I run a combo of OS's at home, and Gentoo is actually my favorite - you can tweak it till you turn blue in the face and still find ways to make it go faster. There is also some pride in creating your own version of an OS as you can with Gentoo, taylored to your specific machine so much, that it won't even run on any other machine than the one you made it for - and this machine specific code will actually run faster because it lacks any bloat and its all compiled for your hardware.
My primary server at home is a Linux Gentoo install.
-S
PS. - WINE -
http://www.winehq.org/ - Information on getting WIndows apps working under WINE -
http://frankscorner.org/ - Seems Silent Hunter III works fine -
http://appdb.winehq.org/appview.php?iVersionId=5618
PPS. Cedega will do pretty much any game out there and is an alternative to Wine, but it costs $$$ for a subscription -
http://www.transgaming.com/