In terms of exclusives I am wondering how the Sony/Valve relationship will evolve. The thing is that Valve is competting head on with Microsoft on the PC through Steam (and winning) and with Sony having allowed them to bring Steam onto the PS3 you could see them starting to favouritize the PS3 as it helps them strenghten Steam further. I don't think they go as far as not releasing a title on the Xbox360, but from their comments so far it seems PS3 owners will at a minimum getting better update support and maybe more DLC etc.
But one thing is sure and that is that I would be extremely surprised if not all Valve games starting from next year doesn't also come out on the PS3.
Would be a wild situation though if Left4Dead3 ended up a PS3 PC title, I almost want to buy popcorn just to see the kind of flamewar that would ensue from such an event :)
