[rab] A congratulations card. If you want to send a present, something for the parents to enjoy, rather than for the child, is better received in my experience. As Projoy says, the sprog is too young to appreciate anything, and it's the parents who will be feeling more in need of TLC, and perhaps a little neglected.
(rab) Can't remember; my nieces were born in 1974 and 1976. It's about time, therefore, that I became a great-uncle and if I were to I'd have a natter on the phone and send a nice card. I wouldn't visit - they'd have enough to do without me getting in the way.