You really owe it to yourself to visit KarenWare.com ... This is savvy Karen Kenworthy's gem of a web site.
Karen develops and offers as freeware for personal use a diverse range of extremely useful Power Tools (designed to run on Windows 95 and later versions).
As well as the tools themselves, you can (and should) enrol for her free newsletter which is not only quite entertaining but also erudite.
If you purchase a copy of her Power Tools on CD Karen also grants you a license to use them at work. I was impressed enough to purchase the CD -- which speaks volumes for the tools because it takes a lot to extract even a dollar or two from me!
For the programmers amongst you, she provides Visual Basic source code for each tool. And you're sure to be switched on by her clear and insightful discussions about a wide range of topics such as hashing algorithms (her Hasher tool) and ultra-high-precision arithmetic (her Calculator which defaults to a mere 10,000 digits precision but she says can be set much higher).
Whether you're a programmer or not, Karen's little beauties are something you shouldn't do without.