Joust, Galaga, Donkey Kong, and Choplifter on Atari were all my favorites as a kid. We graduated to a Nintendo and a Sega when I was in late elementary school, but I didn't like anything but Sonic the Hedgehog.
Not only do I still own my Atari and games, but it's in a reachable location where I can pull it right out and hook it up when I feel like playing.