Like many, many others, I have been urging people to stop using Microsoft Internet Explorer for years. Finally, Microsoft is starting to come around to part of our argument, and has launched a website called IE6 Countdown. Welcome to the party, Microsoft.
My biggest problem with IE is still the fact that it is an integral part of Microsoft Windows. It ties into the kernel of the OS in a way no other browser is able to do, and in a way which no other default browser on any other OS does.
My second biggest problem is the fact that many websites still demand IE to work properly, and many tools do not work at all in other browsers.
Once these to issues are resolved, and some major improvements are made to IE, I just might start using it actively. For now, I will stay with alternative browsers.
For a more in-depth explanation of my issues with IE, read this: Why I choose.