I love all my games and it also depends on my mood...but:
1. PoTC: Great (unorthodox) shots and code. Fantastic depth. Turn up the sound! Dim the lights! It feels like you're playing a movie in a movie theater. IMO it's about as immersive an experience as pinball can get.
2. AFM. Relatively simple, yet deep enough for most of we pinball mortals. Nice shots, perhaps the ultimate classical "fan layout". Perhaps the #1 "just one more game" of all time.
3. Twilight Zone. Another simple, yet deep game from the 90's. Addictive gameplay that's a bit more cerebral than AFM. The ball shoots into orbits or finds its way into the dusty corners of "Twilight's" attic. Go for door panels/modes. Go for Powerball. Go for the Camera. Town Square Madness. An upper PF controlled by magnets(!).