I'm the exact same way. I used to use IE all the time, but once I discovered Firefox, I switched permanently. Tried Chrome long after using Firefox and loved that even more. IE8 was slow and didn't have most of the features I loved about Chrome/Firefox.

The thing I'm dreading, though, is all the computer in the office getting the IE9 update and having to deal with that all over again. (Some computers I've updated to 7, then 8, now it'll be 7,then 8, then 9.. joy)