I've been a fan of Microsoft and Internet Explorer for a long time but when I started at my new job as a C# developer, developing mainly webapplications, I was enlightened by a colleague.
Internet Explorer has many, many flaws. I've been aware of the security flaws for a long time but thought that as long as I ran windowsupdate on a regular basis nothing would happen, and I was right about that. But there was another aspect to it that I hadn't been paying much attention to i.e. standard-support.
As a developer you get very aware of these things when you first make a site according to the standards set up by w3c and then have to redo alot of it just to fit Microsoft's needs. If Microsoft would have followed the set standard there would be no problems.
A big issue in all of this is that alot of people use Internet Explorer only because it is the standard Internet browser installed with the Operating System. This cripples the further evolution of Internet as an information sharing system. Internet Explorer will never become better if it gets no competition.
Recently the Mozilla Foundation has launched www.spreadfirefox.com which is a site to promote Firefox as a better alternative to other Internet browsers. Since the 1.0 PR version of Firefox was released the stats have begun to change in Firefox favor compared to Internet Explorer. This is a good thing since it forces Microsoft to continue it's development of Internet Explorer to keep up.
Hopefully more and more people will realize that Internet Explorer isn't the best choice just because it comes with the Operating System. Click the Firefox button on your right and be a part of an Internet revolution!