A new version of Ubuntu Tweak has been released today: 0.5.5. There's no official announcement yet, but the new version is now available in the Ubuntu Tweak stable PPA.
Looking and the BZR changelog, there's only one new major feature in Ubuntu Tweak 0.5.5:PPA Purge (which was also available in the WebUpd8 PPA by the way), which you can now use from within Ubuntu Tweak.
PPA Purge can remove a PPA and downgrade all the packages you've installed from that PPA to the official version in the Ubuntu repositories. An example: suppose you add the c-korn/vlc PPA and install VLC 1.1.1 but you want to go back to VLC 1.0.6 which is available in the Ubuntu official repositories. Using PPA Purge, the c-korn/vlc PPA will be removed and VLC 1.1.1 will be downgraded to version 1.0.6 (there's one catch though: make sure you don't have any other PPAs with VLC 1.1.1 or 1.1.0 and so on).
PPA Purge can be found in Ubuntu Tweak under Applications > Package Cleaner.
Ubuntu Tweak 0.5.5 also brings support for Ubuntu 10.10 Maverick Meerkat and also, itcan now detect if you're using Ubuntu Netbook Edition or Lubuntu.
Install Ubuntu Tweak 0.5.5:
sudo add-apt-repository ppa:tualatrix/ppa
sudo apt-get update
sudo apt-get install ubuntu-tweak
Note: The Ubuntu Tweak "About" dialog currently says "0.5.4.1" instead of "0.5.5". That's a display bug, if you have the Ubuntu Tweak PPA added and upgrade, you'll have version 0.5.5.