For most internet users, no browser will make a significant difference that will change your life.
I have not liked how IE tab works in Firefox.
I currently have all four major browsers on my computer for testing our applications.
Safari = simply don't use it unless your on the iPhone
Chrome = great browser; i think this is the future #1 browser (barring any other real players coming on board that are better)
Firefox = as overhyped as Mac computers

; it's a great browser but it's not changing anyone's life
Internet Explorer = if you are still using IE6, there are serious differences; IE8 is in the same class as FF and Chrome