Blogbot
Blogbot integrates RSS feeds into Microsoft Outlook without any fuss, and I couldn't have lived without it before Outlook 2007. RSS functionality now comes built-in to the client, but for all previous versions of Outlook this program is an ideal substitute for constantly checking websites for updates - simply sit back and let the web come right into your inbox!
CCleaner
A great little program for cleaning up your PC in seconds - removing index.dat and temporary files, tidying the registry and supporting a wide variety of 3rd party software. Also features an attractive bloat-free design and smart cookie deletion management.
Messenger Plus! Live
This popular and polished add-on for Windows Live Messenger (formerly MSN Messenger) includes many great features for improved instant messaging, including full chat logging, tabs, custom sounds and POP3 e-mail account detection. Includes optional sponsor program (not recommended).
GiFFY
Use GiFFY to convert bmp to gif files - including transparency, interlaced, and non-interlaced images - with a small file size.
Note - I am offering this for download myself after it was removed from the developer's website. I do this within my rights as stated in the program's documentation that "program is FREE to distribute on any kind of media".
Graph
Graph comes in useful for my A-Level Maths homework, and it seems like a useful thing to have on your PC in any case. Very simply, it plots graphs!
FTP Surfer
Despite its last release being in 2001, I've never yet found a better FTP program for my personal needs, including maintaining this website. Particularly important is the ability to edit files 'on the fly' with any changes uploaded automatically.
Spybot - Search and Destroy
It's quite scary the amount of users whose machines are completely infested with spyware and other scum, which can spawn unwanted pop ups, crash your PC, clutter your favourites with junk and even connect to premium rate diallers. Spybot scans your PC for these pests, and even provides an immunization feature for pro-active protection. I also like the other helpful tools provided for advanced users.
The other good anti-spyware products which I use are Ad-aware and Hijack This, although you are not advised to use the latter unless you have expert help since it is not designed to discriminate between malware and legitimate programs. The new kid on the block, Windows Defender, is also well worth a look.