TZ certainly deserves the "King" title. It has a great rule set and is challenging to play.
I think that Cirqus Voltaire is amazing as well. Any one of them would be my dream DMD.
Gotta admit I prefer the 70 & 80's machines where you really play the machine. Out of these I wouldn't know where to start. But at this stage are still within reach of most people. What the hell lets say Firepower, actually Space Invaders or..... Bugger.