Slowly Cleaning Up My Computer

[filkertom]

I've been checking out a few free utilities suggested by Maximum PC magazine. The two most helpful thus far are WinDirStat, which gives you a gorgeous and easy-to-work-with display of your files, showing exactly what's eating up your drive space, and Foxit PDF Reader, which is only about 1 MB, opens almost instantly, and doesn't have the damned Adobe Gamma thing running in the background.

Any good free software you've been using a lot lately? Please state what operating system it's for.