Mega Pixels refers to the image sensor the camera captures the picture with. The higher the number, the better your resolution or clarity of your shots will be, especially zoomed in. I have a cheap little Kodak MD853 with 8.2 mega pixels and for a little camera it takes really nice pics, but I've never tried making a video with it. Yet.
The 1080p is the output signal from the camera to a monitor or your PC, so in that sense it is a better output signal. Frankly, tho, I don't see a lot of HD on You Tube at 1080p. Maybe 720. That's a lot of bandwidth for 1080p.
Guess I would go with higher MP and not worry so much about HD. But you won't find a heck of a lot for $200 or less.

(and RC cars and trucks)
