I make a living from photography and when we come to Disney I always bring my camera bag, alot of different lenses, two camera bodies, and a tripod. This way when I am at a slower pace I can walk around and take my time finding subjects to photograph. But in all honesty, most of the time I carry a waist pack that holds my canon powershot with a couple of extra cards and a battery; the point and shoot takes almost all of our memorable shots and they look great when put on a dvd as a slideshow with music. So don't burden yourself with what camera to use because the most memorable photos are shot from the hip so to speak. Remember that your there to enjoy the moment and not worry about getting the picture right.
As I tell my other photographers, "if you see it happen, it's already to late to photograph."
tom
p.s. Love the picture of your son!
I think I may upgrade to the Lumix, keep that in a waist pack, and just enjoy! I know what you mean about just enjoying the moment - it's why I've resisted trying anything more elaborate! At my current lack-of-skill level 
, I'd miss all the good shots! I'll save that practice for later some time. 
We're going to our first MNSSHP in a few months and I wish I could get good night shots, though - wish me luck!
