Microsoft supported Toshiba in its ill fated HD-DVD push. As a rival of Sony (Sony was the largest backer of Blu-Ray) Microsoft will not want to help out Blu-Ray. Though now that it is the new HD standard, look for a 360 Blu-Ray drive in the next year.
As far as games are concerned, the 360 cannot read any high-def format disks, it doesn't have the lasers required for it.