On Mac, it's mostly between Safari, Chrome and FireFox. I use Camino (http://caminobrowser.org/), but that's basically an OS X front end for FF minus the plugins and other stuff that can bog down FF.
Safari's interface has become to gimmicky for my liking.
Chrome is nice, as long as you feel comfortable providing Google with every last detail of your online behavior. Personally, I'll pass.
The choice, imo anyway, is pretty simple.