As a web developer, MSIE has caused me nothing but hell. Versions 7 and 8 improved a lot, but they still have very annoying headaches that I am constantly dealing with.
One of my biggest fantasies is Microsoft one day realizing how much they HURT rather than HINDER the web, and just throwing in the towel. "We give up."
Developing their own browser does nothing for Microsoft anyways. It's not like using MSIE makes you special or makes your brand awareness of Microsoft any stronger. If they had any forethought for the future, they would just give up now. One can fantasize, anyways... :P