It's not going to kill IE.
The simple fact is that there are a lot of web based ASPs that require IE. My company has an application that I have to use, and it simply will NOT work with anything but IE. I've tried Netscape, Firefox, Mozila, Opera, and Conqueror (sp?).
Nothing but IE will work.
So I use IE for that and WindowsUpdate. Firefox for everything else.
Mark