After having investigated – and obviously used Windows for a number of years in professional and non professional circumstances I have decided that it is undoubtedly better if you keep Internet Explorer as default web browser.
It is more or less integrated with Windows and I believe it just works better (and feels wrong) to set anything else above it.
As an adamant Mac user I have found the Internet Explorer 9 Beta to be fantastic, and recommend you check it out.
Let me know what you think?