I am always interested in this, so I will ask. Is there a reason you use Firefox over IE? Are you a radical Bill Gates hater or is there another reason?
Since you are interested, I use IE most of the time, but as someone who is occasionally forced into doing a little web programming for my company, IE has driven me nuts. First, several years ago, for some reason, MS had to have their own Java VM. I found that a number of "traditional" java classes had functions that just didn't work. Not suprisingly, the equivalent function in the equivalent MS class worked fine. While browsing the MS TechNet groups, I saw that other users ran into the same problems. I wasted much time working around these issues. At least MS gave up on their Java VM.
My company has a small, very simple website that runs on the Programmable Logic Controller that we use in our equipment. The website provides an interface to monitor the equipment. The pages are actually pretty simple, and work fine in IE5, IE6, FF, Opera, and Opera mini. For some reason that neither we nor the manufacturer of the PLC could figure out, the wepages (not just ours) no longer worked with with IE7. The webserver in the PLC constantly refreshes the pages in the browser, and after a short period, IE7 just locked up and stopped updating.
It seems that on some computers, a recent IE7 update fixed the problem, but not on all computers. Since it's still not completely resolved, we just tell our customers to get FireFox (or IE6 if they insist on a MS product).
MS stuff is just...buggy...I'll spare you the details of another MS programming horror story...Bugs in Office 97 broke a number of critical Excel/VBA applications when we upgraded from Office 95 to Office 97 back in the late 90's. We lost a bunch of time and money making things work that shouldn't have been broken in the first place.