I only use IE for Windows Updates and for the few web sites that don't support Firebird that I need access to. I inform the Webmasters in cases like that though.
Which all to often is met by a reply such as, "Sorry but we are unable to support that feature at this time.". Which roughly translates to, "We're to stupid or lazy to implement a non-MS piece of software." Is it really nessisary to build sites with frontpage? I think not.