Besides several of the already mentioned extensions (Thanks for the info on Spellbound Derleth.) I like these.
Bookmark Duplicate Detector - Cleaned out extra bookmarks and warns me everytime I am about to bookmark something I already have listed.
Bookmarks Synchronizer 3 - Copy your bookmarks to a safe spot on the web. Download them to any computer you are using Firefox on. I use it to keep my laptop and desktop matched up.
BugMeNot - A way to avoid registering on all the websites that want your name and email.
IE View - For those websites that refuse to create standards compliant pages. Click the button and IE opens up to that page.
mrrealtime: I think the best reason to switch is security, myself. (See above for my cites, or wait until MSIE has its next OMGWTFBBQ security breach.) Everything else, including extensions, is gravy.
Got a question about this. Is FF a more efficient browser than IE due to tabbed browsing? I can see with a 1-to-1 relationship IE giving better performance due to it’s integration, but considering I need to typically have 3 or 4 windows open at a time (versus 3 or 4 tabs in one FF browser) is there an improvement in wasted resources? Or is the tabs vs. windows differential purely superficial?