Well, don't just run out and buy the now $49.99 HD-DVD player add-on for XBox 360, as Microsoft has no plans to support either HD-DVD or the Blu-ray player yet. Aaron Greenberg, group product manager for Xbox 360, commented
Xbox is not currently in talks with Sony or the Blu-ray Association to integrate Blu-ray into the Xbox experience
Microsoft has stopped making the HD-DVD add-on player for XBox 360 and would continue to invest in the XBox Live online medium. Microsoft has recently started renting HD quality movies on Xbox Live.
So it has to be seen what Microsoft does in future. I guess they have to develop a Blu-ray player add-on.