- Browsing History (also in Address bar)
- Cookies
- Downloaded Files History
- Disk Cache
- Saved Form Information
- Sending of ReferrerHeader

None of the affected options gets cleared totally as opposed to some other extensions which enable you to wipe these privacy issues with a single click, but at the same time leaving you without the history of your frequently visited websites.
Usage:
- [Tools / Stealther] menu option
- Toolbar button
- Statusbar icon (thank you Dreadnaut)
- [Ctrl+Shift+S] keyboard shortcut (customizable)
Enjoy!