Funny, we're having the exact opposite experience.
I find that with every release of Firefox, I need less and less addons. Better dev tools? Okay, goodbye Firebug. Download popover instead of a different window? Goodbye DownloadStatusBar. Australis? Goodbye Firefox-button mover and FXChrome (I use Tree Style Tabs, but FXChrome make everything else look prettier anyway).
I find that with every release of Firefox, I need less and less addons. Better dev tools? Okay, goodbye Firebug. Download popover instead of a different window? Goodbye DownloadStatusBar. Australis? Goodbye Firefox-button mover and FXChrome (I use Tree Style Tabs, but FXChrome make everything else look prettier anyway).