Heh, interesting.
I don't think "of course they change" is reall all that true. The Shaman, for example, has stated that while he might try this or that game, his tastes have remained fairly stable.
I think I'm on the other end of the spectrum here. Every campaign is different from the last one. Different in style, focus, theme and actual play. Like I said, one campaign might be almost free form, high rp, amateur thespian hour while the next might be an old school dungeon crawl, exploration type game.
Even ranging back further, I know my tastes have ranged all over the place. I love the classic Gygax modules. With a passion. They were great. I also loved the Dragonlance modules too. And those two concepts are pretty darn far apart, even if they are both set in D&D.
Heck, in the past year I've either run or played the following: Savage Worlds - SF survival horror, Sufficiently Advanced - very conceptual based, highly philosophical, a variant of Sufficiently Advanced based on Terry Pratchett (hillarious and loads of fun), 3.5 D&D (Shackled City), 4.0 D&D (mostly fairly traditional D&D games).
I'm just all over the place.