...apart from the usual "It hurts!" and anything related to the birth itself.
Mine were:
a) Don't necessarily expect to feel overwhelming love for your baby as soon as you see it... it took weeks before I felt that gut-wrenching emotion, but omg, when I did....
b) As soon as is humanly possible, ensure your baby can get to sleep on his own, without being fed/rocked/cuddled/sung to/driven round the block in the back seat of the car.
c) Never compare your stunningly beautiful, brilliant child to anyone else's, because they will always be able to do something that yours can't, and you'll feel as though you've failed!
...any more?