Microsoft dosn't really want to fully support either format, Blu-Ray or HD-DVD, as they want downloadable HD films to win, Xbox Live already has the video marketplace with HD films to download at the moment. Those rumors of a Blu-Ray addon have been bouncing around ever since Warner's announcement problem is they won't release that addon till they are certain that HD-DVD is dead.
I don't see why they HAVE to bring out a full system version of the Xbox 360, Microsoft are on track and they are already busy building the next Xbox, and that Xbox will have waited long enough to either a) see which format wins or b) see if the internet improves enough to start buying and downloading games online quickly.
Next year is gonna be interesting for the PS3 Dave, it looks like its actually gonna have a good year with some really good titles and the new Home system (their version of Xbox Live) but I think you are right, they are gonna be too far behind to catch up in time.
PSN/Xbox 360 ID - Ianwoollam