Here are some more FF extentions that I can't live without. Here are the others if you would like to refresh your memory.
This will block all those annoying ads people put all over their sites. You can also use to to block regular images as well. Works great.
This one's a timesaver. Have access to your bookmarks, extentions, themes, history and any other extention you have all in the sidebar.
Have your music player accessable from your toolbar.
Sits in your toolbar and lets you know when there's an update to one of your extentions or themes.
Wizz RSS Reader
The best RSS reader I've found.