I have been playing with quite a few extensions for Firefox to improve its tabbed browsing.
I went two ways:
- Tabbrowser Extensions: it's a great extensions, has everything you want; but it's super slow and buggy
- a mix of tabbed browsing extensions: I ended up with quite a few, and that started to be a pain (see MozillaZine thread for details)
I finally found a happy medium: Tab Mix. A single extension, with almost everything I need. And it's light. Give it a try!