Congrats!
Our daughter is nine weeks old, so I'm only a little bit ahead of you. Maeve loves any song finger-picked, especially Ken Middleton's arrangement of "I'll Fly Away." I think the tab is still on his site.
Otherwise, I don't think it matters so much what you play. Man, wait until you see him/her watching you -- it's pretty much the best thing ever.
Cheers.