Mine is probably Super Nintendo, possibly 64. Super Nintendo has some excellent games, including my favorite game, Super Mario RPG. I had countless hours of fun with the Super Nintendo. 64 had a lot of good multiplayer games, as I think this was its strong point. 007, Fifa 98, Super Smash Bros. among other games that absolutely ruled as multiplayers.
Was never much of an NES player, as my parents couldnt afford it when it came out, and you try getting a job at 4 years old
Never much of a gamebody player either, except for a little Tetris and Pokemon. I loved Pokemon, that game is great. Until I surfed the one place and screwed up my blue version.
The newer systems are all eyecandy. There are very few good games out there that are new. Graphics get in the way of the gameplay that older games used to have plenty of.