No problem, I love talking about linux etc
All *nix based OS's come with a wealth of networking tools (as I am sure you know).
Windows network compatability is also good with samba providing *nix machines with access to windows shares (and vice-versa).
Linux is also becoming increasingly compatable with Windows software (DOS emulation has existed for a long time AFAIK). Wine & WineX (3D support) provide a native linux version of the windows API framework (so not strictly speaking an emulator). This allows Win32 based software to be executed under linux (I play the Windows version of Return to Castle Wolfenstein using WineX). Mandrake are even releasing a "gamers" version of linux that includes WineX support for playing Win32 releases.
If you are into eye-candy then Mac OS X has to be one of the best systems around (you need a mac). Aqua (the GUI) is about as flash as they come. Also being based on BSD it is a solid & relaible platform but needs to mature a little IMHO.
As you can probably tell I am a fan of every MS alternative available (competition is good

).
Regards
Eddy