OS X has a myriad of multi-touch gestures that have been expanded upon from OS X 10.8 Mountain Lion onward, and one of the better gestures is the two-fingered swipe left or right to go either back or forward in a wide variety of apps.
You’ll obviously need a trackpad or Magic Mouse to be able to use these, and they’re supported in a fair amount of Apple apps like Safari, Dictionary, iTunes, App Store, Launchpad, and just about any other app where there’s a forward or back button. For browsing, the gesture can be much faster than navigating to a back or forward button since all it takes is a quick flick to activate.
Unfortunately not all apps support the back/forward gesture yet, but with heavy iOS influences coming to the Mac you can bet more and more apps will support this and others soon.
On a side note, if you’re used to hitting the Delete key to go back a page in Safari and don’t want to use a gesture, that behavior can be restored to the Delete key with a defaults command.