I managed to come across Chris Pirillo's post where he said he was breaking up with Vista. Well his number 2 reason was that Windows Movie Maker crashes on a regular basis. Well I couldn't let that statement go without saying something :-), so I posted a comment offering help.
Chris replied and with some more information from Chris and by utilizing the Watson crash reporting service I managed to track down the crashes to some third party codecs which were installed.
I'm not sure if he ended up uninstalling the codecs or disabling them with the compatibility tab, but he reported that Movie Maker is now working fine.
So although he has other reasons, I'm happy to report that number 2 is no longer one of them :-)