My wife and I sell vintage Hallmark ornaments on eBay, so I have a pretty large list of ones I like a lot... but my personal favorite is the Star Trek 30th Anniversary silver Enterprise with shuttlecraft. It talks, though there's some argument around the house whether it's William Shatner's voice, or Leonard Nimoy's (The audio is kind of fuzzy.)
I like the Superman in the phone booth too - He spins, going from Clark Kent to Superman.
There's so many great ones, it's hard to pick just one! Great question.