My all time favorite is Bally Wizard! The game looks great and plays great. I am lucky enough to own one that plays like it just came out of the box. Most of the ones i have played at shows are pretty slow unfortunately, but if you play fast one, your opinion of the game would change.
There are other ems that i like a lot too. Aztec, Majorettes, Space Mission, Grand Prix and a friend of mine owns a Bally Amigo that I feel is a very underrated game.