tell me your add-ons!

So, I got my PC back today and it's running smooooooooth :)

But there are TONS of things I need to reinstall. One of which was Firefox. Which means I need to reinstall all my add-ons - or at least, the ones I can remember I had [sigh]. Plus any new ones I think might be cool.

But there are so many! So I come to you, my faithful friends, for your guidance.

Tell me your favorite/absolutely necessary add-ons, so I can spiff up my browsing experience :)