When I switched from Windows, I went straight to Firefox because I felt comfortable there. But (3 years ago), Firefox started getting buggy and slow. I loved the add-ons, but I switched to Camino because it was more Mac-like and stable. But since Beta 3 for Firefox came out, I've switched back and been really impressed with it.
One feature that Firefox and Camino both have is the "Search for text when I start typing" which I use a lot for mouseless navigation.
I don't have any major gripes against Safari, I just prefer Firefox.
The GrApple Delicious theme for firefox is a must have for any Mac user.