I'm not sure what's left after Chrome and FF. Safari if you are on a Mac and IE on Windows (though IE seems imperfect). I suppose you can use a FF derivative like Ice Weasel. For my money, Mozilla is still the best option and with so many free options out there, it's hard to keep up unless you play the game somewhat. Mozilla's most important role is a seat at the web standards table and if they wither on the vine because users jump to Chrome because it "just works", they will lose that seat.