lets go up with this topic, this is alltime interest :
1. Donkey Kong (and DK2)
2. Wonderboy
3. 1942
4. Galaga
5. Mr. Do
6. Pacman
6. R-Type
8. Donkey Kong 3
9. Xevious
10. Time Pilot
All this games i have played between 1980 - 1990 on original machines.
( ok, without DK2 and DK3 )
There are more games, they should be at the top 10 too:
Eyes, Pole Position, Nemesis, Slap Fight, Terra Cresta, Elevator Action, Moon Patrol,
Traverse USA, Hyper Olympic, Venus (Gyruss), 1943, Nova 2001, West Bank,
Dig Dug, Prehistoric Island, Commando, Jumping Jack, Zaxxon, Circus Charlie, Bomb Jack,
Gang Busters (again, the most played original too)