I cant stand Safari, i used to swear by it, but now whenever i try to minimize a window or tab (i usually have 4 or 5 windows open at once) the whole program goes to my dock and it drives me insane, Firefox is much more practical for me.
Also firefox has a new feature called Ubiquity that you can addon yourself, which whilst i know isnt completely finished already works amazingly well, and once you use it you wont be able to live without it anymore, if I had to ever delete Ubiquity now then it would be like cutting my hands off, its the next major step for the internet in my opinion and its going to blow browsers like IE and Safari out of the water.
Watch the vid if you dont know what its about:
http://labs.mozilla.com/projects/ubiquity/