I think gifts of practical items like Christy suggested are a great idea. I know I recently bought a friend of mine a box of nappies as a gift and she really appreciated that! The things like wipes, nappies, wraps, nice baby products (shampoo and the like) are always great gifts I think.

A new photo album is a great idea too, or perhaps one of those books that you record the baby's milestones in?