I still have my old Atari, before it was called the 2600. I still play Night Driver, the very first game console driving game, and Kaboom!, Breakout, Adventure, Chess, Boxing, Pitfall, Pitfall II, River Raid, Barnstorming, Freeway, Space Invaders, Defender, Chopper Command and Starmaster.
I also still have my old Commodore 128. It was the model after the 64. I loved playing games like Montazuma's Revenge, Lazy Bone Jones, Route to India, Air Comabat Simulator, Leaderboard, Blizzard Attack, Yie-Ar(sp?) Kung Fu, Beach Head, Blue Max and one other game I can't recall the name of, but was similar to Beach Head.
But, my oldest game has to be my old hand held Classic Football II, and Classic Basball games made by Mattel. My 7 year-old boy loves them too. I once had an old Pac Man hand held, but my brother lost it when we lived in Holland. This hand held game looked just like an arcade game. If I remember correctly, Coleco made them.