I like Geeky things.
1. Asteroids (1979)Almost flawless in it's smooth loveliness.
2. Tempest (1980)Pure adrenaline hectic madness.
3. Bubble Bobble (1986)Super joys of strange sweety bonuses. plus proper multiplayer. plus dragons. plus bubbles. plus "Grab the fucking umbrella".
4. Rainbow Islands (1987)The amount of depth in this if you get good at it is ridiculous. I'm not very good. Still love it though.
5. Bomb Jack (1984)Simple yet fun. Has a beepy version of Lady Madonna as it's soundtrack if I'm remembering right.
All been ported with various degrees of goodness to most 8 and 16 bit machines, but it's worth downloading mame and playing the proper original versions without the worry of running out of coins. Good times.
Worthy mentions go to:
Cameltry (1989) - Dizzy inducing fun as you spin an entire maze to try and guide a marble through it
Strider (1989) - Sexy side-scrolling action platforming
Frogger (1981) - Bizarrely addictive despite it's simplicity
Donkey Kong (1981) - Spawned a few things this one, Jumpman got better at jumping when he changed his name;
And in the less oldschooliness, any of the Street fighters (well not the original it's shit). Particularly Street Fighter Alpha 3, and whatever the last Street Fighter II was (Super *** Turbo?). The proper arcade versions are the bestest.
You can probably tell I'm a bit bored. I'm not sure I'll get anybody else giving a top 5. Oh well.