Depending on your objectives, heres what I think you should pick as a browser:
If you want speed: Pick Google Chrome, Opera or Safari
If you want extended functionality: Pick Mozilla Firefox
If you want to get fucking owned by malware and have a shitty slow browser: Pick Internet Explorer.
Personally I use Mozilla Firefox. Why? Because I use a lot of the incredible add-ons such as Bugzilla, spellchecking (Portuguese and English), adblock plus, noscript, search pics with tineye plugin, Firefox sync, gmail notifier, TOR, Priberam dictionary search tool, and some others.