I recommend Mac users to download the mac-optimized firefox builds. The guy has made builds for G4, G5 and Intel Macs. I’m using the Intel optimized build and it starts up within one bounce on the dock.
Even better is that you can use OS X native form widgets (”form widgets” are like those thingys you see on the page that help you interact with the page). For example:
Right at the bottom of this picture you can see the drop down list in the browser, the scrollbar thingy is Aqua blue. It doesn’t really make much of a difference apart from how it looks, but I prefer Aqua. 
