I'd like a 10" or 11" screen with one side e-ink and other side AMOLED, multiple microSD cards, wi-fi, bluetooth, 3G, 1080p video/camera and whatever else they can come up with. Vertical/horizontal scroll pads would be really nice.
Give it 3GB of RAM, let us run Android and Win7. Give it one of those new Atoms with integrated gfx. 16GB/32 super fast SSD should be fine.