i'd just recommend firefox, especially the new firefox 4 beta. they're up to the 11th beta version, i think, and it's realy great. stable and it runs everything.
the only thing that safari has on it, in my experience, is that it's easier to go to ssecure websites whose certificate, for whatever reason, has changed since your last visit. for me, this means my router every time i reboot it, and maybe a banking site or two every so often.
i don't use any other, don't think i've tried any others on mac. not worth it, IMO.