On to the first freebie, CCleaner! This one is a must-have for those who want their PC's clean, faster and more efficient (who doesn't?). Personally, it has proven itself worthy of a place in my hard drive. It certainly delivers what it promises. Try it out on a PC with excessive YouTube abuse for instance, and you will certainly be surprised at how much space it frees--mine got up to 2 gigs of freed memory.

Description:

CCleaner (formerly Crap Cleaner) is a freeware system optimization and privacy tool. It removes unused and temporary files from your system - allowing Windows to run faster, more efficiently and giving you more hard disk space. The best part is that it's fast! (normally taking less than a second to run) and Free.

Cleans the following:

* Internet Explorer Cache, History, Cookies, Index.dat.
* Recycle Bin, Temporary files and Log files.
* Recently opened URLs and files.
* Third-party application temp files and recent file lists (MRUs).
Including: Firefox, Opera, Media Player, eMule, Kazaa, Google Toolbar, Netscape, Office XP, Nero, Adobe Acrobat, WinRAR, WinAce, WinZip and more...
* Advanced Registry scanner and cleaner to remove unused and old entries.
Including File Extensions, ActiveX Controls, ClassIDs, ProgIDs, Uninstallers, Shared DLLs, Fonts, Help Files, Application Paths, Icons, Invalid Shortcuts and more... Backup for registry clean.
* Windows Startup tool.

CCleaner official site