Another vote for opera. Yes firefox is good and fast, but being able to open your browser and have it load three forums and a news site or two automaticly (and log you in) is just too useful.
The default mouse gestures in opera are more intuitive than the radial menu thing I downloaded for fire fox. In opera it is a gesture. Drag mouse left-and right click to go back, hold right click move mouse right-left-right to close a tab. Firefox is easier but not as quick. Firefox is: press middle mouse button which pops up a circle with back, forward, and close tab buttons on it.
I say use opera for daily haunts and fire fox for browsing. Fire fox also has a search engine menu that you can add a whole list of sites too, my most recent version of opera (probably not the current release) only has a fe default sites to search with.