It may be just talks at the moment, but I was very interested in hearing that Sony and Microsoft are discussing a potential future marriage for Blu-ray and the Xbox 360. Even though Microsoft is directly competing against the PlayStation 3, they are still open to the idea. They have come a long way from when they were absolutely not willing to consider Blu-ray units on their beloved console.
Whether as an integrated component in future iterations of the console or a plug-in that can be bought off the shelf, it would probably be in Microsoft's best interest to offer it. As the number of titles offered for the PS3 increases, Microsoft will need more added value to keep people interested on their console.