I have a win2k box though most of my development is for linux. Stuff I wouldn't do without:

• GNU utilities for Win32 - win32 ports of many unix tools, wget, gzip, tar, less, uniq, sort, ls, etc. Wouldn't be able to survive without this.
• TweakUI - gets you tab completion
• NMAKE - for module installs
• Infozip - command line ZIP tools
• ActiveState - I use ActivePerl, Komodo and perlexe on a regular basis
• VIM - editor of choice on linux, I use Komodo mainly on win32
• Outlook Express quote fixer very handy if you use OE
• HTTrack - very powerful website copying tool (works better than wget)
• Popcorn - tiny little POP3 client, great for testing
• Irfanview - nice little freeware imageview/batch converter
• Imagemagick
• Textpad - another good editor
• Mysqlfront - MySQL gui
• Leechftp - ftp client

Phew! :)

A bit off topic, but hopefully useful none the less...

gav^