Here's a smattering of software I wouldn't want to be without on my Windows work computer:
FastStone Capture for Windows
This is a great screen capture utility. Unobtrusive, efficient, powerful, simple & easy to use.
Visual differencing and merging tool for Windows.
Free Microsoft tool for synchronizing folder pairs.
Secure password storage program. Main build for Windows; builds available for Linux/Mac and handheld platforms.
Secure screen sharing. Help family and friends with their computer problems.
It's not my primary browser but the developer plugins can be life savers.
Powerful text editor. I know there are others out there that developers like; this is one I've been using for years... it's quite good. Perhaps if I have time I'll play with other text editors I've heard about.
I came across a great little time-tracking utility that I'm using now at Grey:
Back-to-Front Solutions Ltd : TimeCore Solo