By Firefox 3.0 has been officially launched today. Some of the old add-ons from Firefox 2.0 still don't work with 3.0 so I would recommend that if you have an add-on that you desperately need then check and make sure that it's compatible with 3.0 first.
European users can download Firefox 3.0 from here. The US site still lists 2.0.0.14 as the latest version.
You can check add-ons here.
It's definitely more stable and less of a memory hog than previous versions and I would recommend upgrading to 3.0 to everybody and I would also recommend Firefox over Internet Explorer, Safari and Opera.
Cheers for that. Will have to check to see if Firebug works. I do hope so as that is one of the most important ones I use.