Hello,
I dont know if you recently updated the antiphishing toolbar but for some reason it made my firefox 5.0.1 extremely buggy and unstabile today, I got the "(not responding)" message on every single website I tried to open.. I did not have this problem last night.. I tried updating everything, reinstalling firefox etc. but the only thing that resolved my problem was to disable your antiphishing toolbar 2.0...
Just wanted to give you guys a heads up on this.
I'm running on Windows 7 x64 (32 bit FireFox though).
I have not made any changes on my system since last night.