CCleaner is a freeware system optimization, privacy and cleaning tool. It removes unused files from your system - allowing Windows to run faster and freeing up valuable hard disk space. It also cleans traces of your online activities such as your Internet history. Additionally it contains a fully featured registry cleaner. But the best part is that it's fast (normally taking less than a second to run) and contains NO Spyware or Adware! :)

Cleans the following:
Internet Explorer
Firefox
Google Chrome
Opera
Safari
Windows - Recycle Bin, Recent Documents, Temporary files and Log files.
Registry cleaner
Third-party applications
100% Spyware FREE

Source: www.piriform.com