Here's a complete list for you
I think a lot of people are using this as a stick to bash MS but with no real reason...it's very rare that everything supports/works with everything so this is nothing awful.
Whether it's MS's or Intel's fault doesn't really matter, it is what it is and the vast majority of people will have HAV capable CPU's...certainly the most of the people likely to run XP Mode.
However it is a bit of a confusing situation so I'ev put together a list of all the Intel chips that do and don't support VT:
http://richfrombechtle.wordpress.com/2009/05/01/windows-7-xp-mode-pre-requisite/