SiSoft Sandra - A super suite of system tools - the Standard version is free for personal and educational use, but buy it anyway. It's only $29 a machine. And it rocks.Kelly's XP Korner - An on-line encyclopedia with all kinds of information, help, and tweaks for XP users.
Sysinternals - Great freeware utilities for Windows and Linux. TCPView is especially useful - it displays all your TCP traffic, attached to the thread that generated it. And then there's FileMon, and RegMon, and they're just all things you should never have to live without.
Scrapture is a wonderful screen capture program for Windows. It saves the name of the current process as the filename, along with a timestamp. So you can just capture away. Use it with vjpeg, the cutest jpeg viewer ever.
UltraEdit32 - This is my all-time favorite text editor. Fast to load and great features - notepad on steroids.
Mantis BugTracker - A solid free php/SQL bug tracking database program. The UI can be dang frustrating at times, but after the past several months, I've actually come to really like it.
TweakUI - A useful little program that gives you access to all kinds of hidden and unsupported Windows features.
Google's Zeitgeist - Along with all the popular search terms of the moment, Google publishes information on Operating Systems and web browsers used to access their site. Great information to have while planning compatibility testing.
Sephora.com - Ever since the ill-fated eve.com shut down, this is just the best way to spoil yourself after a rough shipping cycle. They still carry (almost) the full line of Demeter fragrances.
Amulet Jewelry - Waiting for a build? Custom design your own jewelry - you can pick jewels and settings. These guys are a tiny shop out of Sonoma CA, and they do nice work - I have ordered several pieces from them and am very happy with the prices, quality of work, and service.