I agree with the couple of others that find all the MM votes undeserved. I consider it a fancy bash toy. I guess I'm missing something on the STTNG Borg ship also...what does it do besides occasionally / rarely spit a ball out?
A lot of good ones listed here though. Twister and Lost in Space magnet spin looks cool. Rudy got a whole lot cooler when I realized his eyes follow the ball. I like the Johnny glove. Pirate ship is cool...I also like the spinning target area that Pirates and some other games use. I like Stewie / Donkey pinball, the wand on Pinball Magic and the jump rope on Champ Pub (even though I do terrible at it). The outlane ball save on TOTAN is also extremely cool, but I don't know if I would call it a toy.
If I were going to pick a winner though....I would probably say the crane on BTDK. I haven't played it much but having a physical moving target is really cool. Cooler than hitting a Big Buck or a Mick Jagger, but they are fun too. Someone mentioned the crane on LAH in compairason to the Batman crane. There really is no compairison except they are both cranes. The one on LAH is just used to transport a ball to the lock area. Fun, but not as impressive or interactive as the crane on Batman.