Have you seen the prices of the XBOX 360 HD player? Used to be like $250. Now its $50! lol Since PS3 is Blu-Ray already I would guess PS3 will get bigger but heres the catch:
We asked the guys at Best Buy why we would want to buy a Blu-Ray player for $500 when we could buy a PS3 for $399. They told us that the PS3 wasn't really made to watch Blu-Ray movies but to play the games in high def. They said if you use it primarily for movies, the drive will burn up and stop reading discs.
So guess what happened to the PS3 we bought? And not from Best Buy either. Wal-Mart. The drive burned out. So we used our warranty and replaced it. Guess what happened to it? That's right. Drive went out.
So I would say that if the Xbox comes out with a separate Blu-Ray player just for movies, then Xbox will definitely come out on top.