I have long been a fan of Firefox but since version 1.6.6 it has turned into a nightmare. Firefox has become really slow, it crashes and can not recover from the crashes even if you reload the browser in safe mode. I had to remove and reinstall it to solve the problem. Too much hassle.
Chrome is fast and stable. I have yet to see it crash (and yes, I have also added a few extensions). Chrome has become my primary browser now.
Firefox remains the development browser of my choice until Chrome catches up with extensions for development.