[RealJames]

I use
FF3 and FF4 (Beta) Flock
Chrome and Chrome Beta
IE6 through to IE9 (Check out a program called IE Tester)
Opera and Opera mini
and Lunascape (lunascape.jp check it out, Japanese browser, love it, loosely ff based kinda like Flock, which is also very nice!)

I use them all because I need to check how the webpages I design look in them all, and honestly some sites load faster in some browsers than in others, it's inconsistent, and the differences in speed are getting so close it's almost not a factor anymore. The important thing is becoming what features you like

They all have the bigger area and nice new tab features etc.
Mouse gestures can be found on all of them too, some more easily.

My preference is FF(beta) because I use greasemonkey, adblock, mouse gestures, firebug, webmail adblocker, the tab-groups, and the personas plugin for skinning.