Oh, and I hadn't known that NPH was the voice on California Screamin. Probably the only good thing you can find on that ride.
What about Gary Sinise (aka Lt. Dan) doing Mission: Space at epcot?
Personally, I was always a bigger fan of hearing Jeremy Irons on the Spaceship Earth voiceover. Nothing like hearing Scar or Simon Gruber telling me about the history of communication.
While at the Disney Cruise and Hong Kong Disneyland, you get to see CEO Robert Iger in the Golden Mickeys show. I think most people don't know who he is although I do and thought it was just weird to see the CEO in the show.
Of course, if we include Body Wars, we'll also have to include Cranium Command and that might take a while.