Arrandale is the first order of business. With intel having this ready in a few weeks, there's no reason for apple to update the MBP line using the current chipset.
Given that arrandale contains its own integrated GPU, its really up in the air what apple will do. Stick with nvidia, and require intel to provide one w/o the GPU. Ignore the integrated GPU and go with a discrete one or just live with the intel GPU.
Larger SSDs as an option
BlueRay would be nice, but I'm not holding my breath
That's about it, there's not much more you can add to a laptop, perhaps increase the max ram beyond 8 but even then, I'm not sure if that's needed quite yet,i.e., 8gig is probably more then enough for 99% of the users at this stage.