I think I'm only using the first or second version of Firefox. I've been pleased with it and haven't had any problems on here or any other site.
On the other hand, iTunes 6.0 totally crashed on my computer the first four or five times i used it. It seems to have stabilized now, I'm not sure but I think it had something to do with the quicktime addon. I got it to download Lost episodes in case I miss one (yeah I'm addicted) but I should have kept 4.0 or whatever I was using and just set the VCR.