I didn't read all of the replies, but I'm just throwing my 2 cents' worth in the thread.
I would believe that they are dropping nVidia chipsets for upcoming models, because of the licensing issues. I think that Intel can probably do it better anyway with their onboard memory controller (is this new? I don't even know) and the new advances with its upcoming platforms. Fortunately, the removal of the nVidia chipset makes more room for dedicated graphics chips across the board (we have 2 chips currently, with Intel's CPU/Chipset combo, we'd have 1 chip with physical space for a second, ie: a GPU).
Also, with the upcoming Open CL that was so highly pushed, I doubt that Apple would abandon that technology in roughly half of it's machines.
So I think we will start seeing dedicated GPU's across the board, whether from nVidia or ATI.