It's amazing how much offspring the konqueror-derived webkit browser engine has created. I think it's a good hint to see how high the code quality of kde and qt is generally. One of the newest offspring is vimprobable. It's a browser that focusses on keyboard controllability. And it has a really fancy AJAX, Flash animated, SQL-Server backed website. ;) ;)
It's so fresh, there may not even be packages yet, so you'd have to compile it.
Other non-standard browsers of my readers include Opera Mini (.5%) (ok, that's the mobile standard), Seamonkey, Midori, "wg" and Playstation 3.