Things that Linux does better than Window$ (IMO):
- all networking stuff: far safer and stabler than Windows. Complete firewall, HTTP server, mail server, Database server, printing services, you-name-it-server functionalities....for free. Compatible with Windows networks thanks to Samba (you can easily access windows shares or mount shares on a Linux box that Windows machines can access.)
- applications and disk management
- less prone to viruses, excellent free antivirus softwares availables
- free but professional software like OpenOffice (see above), The Gimp (~Photoshop), GPG (Gnu Privacy Guard = free PGP, fully compatible with each other), media players, CD/DVD copying, ripping and recording...
Points where Window$ (still) shines:
- games
- more codecs available for media players (i.e. WMV3 is not yet supported under Linux)
- some excellent softwares like DVD-Shrink...