I have a Surfer (1976) and a Super Score (1967) - both old Gottlieb electro-magnetic machines.
All solid-state, although I'm looking for a '67 Williams Apollo. Had a deal on a pristine one a few years ago that fell through at the very last minute. I'm still mad. ;-)
Have Twilight Zone, Tales of the Arabian Nights, Cirqus Voltaire and Revenge from Mars. Have received enormous education, assistance and leads from rec.games.pinball, which I assume you're aware of.
I actually have more fun tinkering with the old things than I do playing them. While both my cabinets are in bad shape (both were rescues), I pride myself on the playing fields - both are very smooth and fast. Both games are set on hi-tap, with all new bumper and flipper coils.
There is nothing like coming home from work and grabbing a cold one and banging out your frustrations on a great game.
Here's a pic of my Super Score game: