OK - I'm hooked on FireFox 3.0 - they corrected a few of the issues and I found work-arounds for the rest. It is faster than the older 2.x versions, and more stable as well.
I use a LOT of add-ons.
Adblock Plus - everyone should have this - it blocks ads.
Better GCal - if you use Google Calendar, this might be good for you
Bookmark Duplicate Detector (Not yet updated for 3.0)
ColorfulTabs - Makes the tabs different colors
ColorZilla - color tools, tells you the color where the cursor is, etc.
Configuration Mania
FireFTP - Insanely great FTP client
FireShot - take a screenshot or save the whole page in various formats.
Foxmarks Bookmark Synchronizer - sync your bookmarks across several computers
IE View - view any page in MSIE
Image Zoom - very nice image tools
infoRSS - RSS reader across the bottom of the browser
Leet Key - text converter - MANY codes, like l33t, hex, octal, etc.
Linkification - makes text links clickable
McAfee SiteAdvisor - security tool
Netcraft Anti-Phishing Toolbar - security tool
NoScript - blocks scripts unless you allow them. Nice, but high-maintenance
Regular Expressions Tester - programming tool
ShowIP - Security tool
Split Browser - nice, but limited use. I might uninstall it
Stylish - excellent - apply your edited CSS to any page, customize it.
Tiny Menu - turns the normal menus across the top bar into a dropdown menu
I also dragged the Bookmarks Toolbar to the top menu bar, so with the Tiny Menu add-on, I have more screen left for browsing. Works nicely.