I use firefox, and while firefox is speedy, its not why i chose firefox back in the day.
It was Ad-Block Plus. The Plugins! Firefox works so well with plugins, and ad-block plus is my favorite one. From what I understand neither IE or Chrome support plugins like firefox does, and can't easily remove the ads.
So until IE allows that (or Chrome) I wouldn't even bother to try a new one.
I do hope we get a 64 bit flash and 64 bit firefox. that'd be sweet.