NoScript: disable scripting and enable it selectively using the F12 "site preferences" shortcut.
AdBlockPlus: You can get various urlfilter.ini if you really want to. I really dont need this, just block the most annoying ones with right-click:block_content. Some sites need the "normal" advertising, and once you block the top-10, you don't have much to complain about. Anyway, I will give you that point.
Flashblock: Here. Myself I just "enable plugins" (F12 again) on sites I want. *And* you can block the flash content with the normal "block content" too.
Firebug: Meh. Have you worked with dragon fly?
RefControl: Hmpf. F12, disable "send referrer information". Maybe it is just me, but I never needed to spoof referrers.
And yes, I use every one of these extensions on firefox, because it is not there as default. And some more. In a *memory-limited VM* just so it does not goes haywire and swaps the hell out of my current apps to oblivion. Lucky me.