I always found Patrick, the preshow host in Soarin', really funny. Since I seldom watch contemporary live-action films or TV, I didn't recognize him as a celebrity right away, but being a HUGE fan of Disney's Animated Classic Features, as soon as he talked I recognized him as Kronk from The Emperor's New Groove.
But anyway I always get a kick out of the thumbs up and "Nice work, pal!"
Ellen is funny in Universe of Energy as well - such as "It's not that I don't like getting attacked by a large, snakelike creature".
Does Goofy count in Mickey's Philharmagic? His dialogue in the preshow area and before the show starts is funny as well - like when he steps on a cat and tries to plug in an electrical plug.
And I like Timothy Q. Mouse's spiel on Dumbo, such as "Now youse can all hold your horses... I mean elephants!"
And the pre-board video from the original Star Tours always cracks me up, as Chewbacca and some Ewoks demonstrate their disdain for flash photography and smoking!