Chrome is fast because of it's minimalistic UI, hopefully Firefox 4.0 will be as minimalistic but keeps having it's functionality which is definitely broader than Chrome's is.
In my opinion;
For just surfing:
Chrome / Internet Explorer / Safari
For Extensions and functionality
Firefox / Opera
All browsers are capable of doing what they're supposed to do, but the latter two have more possibilities.
Firefox has it's extension-base which is larger than any other browser, seemingly it's not that difficult to code your own extension or theme.
Opera has mouse gestures and a mailbox and possibly more but haven't thorougly used it.
I heard lot's of people complain about browsers but I never really understand why, except for being a fanboi.
I read about Chrome being uber-fast, I haven't noticed any actual speedgains while surfing unless it's maybe a few miliseconds compared to Firefox/Opera or Internet Explorer. But some reviews are to biased like with ATI vs Nvidia, where Nvidia uses games that are Nvidia optimized and have Physx(made by Nvidia) so no wonder those games run better on Nvidia cards.