My experience has been as follows. I got the D50 to photograph the little monkey and I'm glad I did. However, I also wish I had a good, small P&S so that I would take it everywhere. To me, the keys for cameras and babies are convenience, speed, low-light capability. Convenience because you never know when you'll want to snap a pic; speed because that first smile is fleeting and then later the kid moves really fast, and low-light capability because it's nice not to have to use the flash.
I've found video to be a pain in the ass.