Not Really Tools so much...
Personally, I use stuff like Combofix (not often and with care), Super Antispyware, Spybot, CCleaner, Puran Defrag, MSE, and a few other less essential packages. Check Majorgeeks.com. They have a nice collection well organized. I've just recently tried the Microsoft Virtual Machine for running 16-bit apps in Windows 7. It works, but it's not a perfect solution. Perhaps the Sun version will be better. I like TestDisk for recovering files from damaged drives. I'm still looking for a tool that will help me find big files and folders easily. I like the duplicate image finder in Picasa, though it's in the experimental menu. It works. These are all free stuff, and IMHO, they're the best I've found, free or not.
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