Two favourite ones:
* Android because has in-depth level like progression not seen until Pro Pinball tables. Also idea for making synthetic to life.
* Cyborgirl aka Cybergirl because it's cyberpunkish table about girl hacking into cyberspace (contrary to what most people believe - it's not cyborg chick ;p)
Others I liked:
Space Journey - because it has that adventure into unknown kind of feel with kickass tune.
Deep Sea - the same but with underwater, more calming.
Pangaea - old times when dinosaurs walked on... interesting implementation of themes with actual rules and features on table.
Annoying, cheap but keep coming back:
Crash and Burn - fast, furious and really feels like participating into racing event and career...