Wow, my premise got owned, at least when it comes to books and old school games. Toy story is definitely a solid trilogy I didn't think of. People mentioned Assassins Creed, Mass Effect and Gears as good trilogies, but I don't think you can count them yet. They are all good starts but so was the Matrix, and so much of what makes a trilogy great (imo) is how it paces itself and wraps things up without getting too crazy. There's no guarantee that they'll be able to do that, especially looking at all the work they've left themselves in the third installment. They're in good hands for sure but I have my doubts.
(I'm not counting Brotherhood because I consider it more of a diversion than a full installment in the story, Assassins Creed 2.5 if you will.)
(I'm not counting Brotherhood because I consider it more of a diversion than a full installment in the story, Assassins Creed 2.5 if you will.)