Firefox kicks incomprehensible amounts of ass while IE sucks. Firefox is more secure than IE, its very customizable (looks and functionality through themes and extensions), great pop up blocker built in, and if there is ever a problem, a fix can be made and released within a day. Oh yeah, and its TABBED BROWSING! That's the greatest thing ever. It's just better. The only problem I have with Firefox is that it never remembers any of my favicons and it doesn't have a reload images thing, just View Image which opens the picture in the same tab instead of just reloading it.