I am actually a fan of MS and really like almost everything they do. However I use Firefox for 1 reason. When I close the browser, or it crashes, it will open again with all the same tabs it closed with. IE7 and 8 kind of do this, but it always involves extra clicks or saving "favorite groups". All more effort then I want to put in.

I also feel much safer with Ad-Blocker and No script in Firefox.

I really wish MS added those 3 features with IE8.