Get your Remote control cars - seriously they are the most awesome christmas present, all kids love em. I brought 4 last year - one for each of the kids and 2 for a nephew and cousin! Everyone loved them.
I personally opt for the petrol cars - but they are a bit more of an adult toy - so I have one for me but I usually buy kids high end electric rc cars, because they are nearly as fast as the petrol radio controlled - but without the chance of the kid spilling petrol anywhere or having to pull the pull cord and not being able to. Electric remote control cars are a bit cleaner to be honest.
This year I got the kids new ones - these ones go nearly 40mph - electric remote control cars that go 40mph? thats mad - you should see the yard, the boy has even managed to master the drifting in gravel so he can drift around everywhere!
