>>5
I'm a personal fan of Firefox [who isn't?], but on my mac I almost always use Safari. I have an adblocking extension from pimpmysafari.com, and that's all I really need. It's a pretty fast browser, simple, and gets the job done. I like it.
Opera is ok. I have it installed on this computer and often play around with it. I would be using it instead of Firefox if Safari didn't blow it away in terms of speed.