The iPad left out:
3G (this should be standard)
2x Cameras for FaceTime
1GB DDR2 RAM
64GB internal memory
Cortex A9 cores
Loudspeakers
Range of colours

.... which were intentional, it gives Apple things to make the iPad2 (or iPad 3G) more superior and gives buyers reasons to make an expensive upgrade.
Apple are evil geniuses, but geniuses either way.