Restyle the web with Stylish, a user styles manager. Stylish lets you easily install themes and skins for Google, Facebook, YouTube, Orkut, and many, many other sites. You can even customize Firefox and other programs themselves.
Automatically find user scripts on Userscripts.org (requires Greasemonkey or Scriptish)
custom additions to Stylish extension.
brings back features from 0.5.9 and adds new features
I can't be bothered to change SC, so amo will allow it to be uploaded
StyleSheet Chooser Plus (aka SSCP) persists choice of website stylesheets.