"I will make monkeys of these monkeys, for it is their destiny!"
Vlad choking on a bone. "Holy moly!"
The entire breakfast sequence, including Sally's motherly but offhanded "That's one of my girls!"
The portraits of the various ancestors... including the "... not-so-great" grandfather.
THE ANIMATION. Never before have CG characters squashed-and-stretched so much as in this film and the animators utilized it to great effect, eliminating any doubt that CG models can move just like hand-drawn characters!
The business with the two Vlads- the bad Vlad... and the bunny Vlad that makes the cookies!
"How could he call me a boob? I would never call anyone a boob. HE'S the boob!"
Later, Horton gets the chance to threateningly call the Chairman a boob, scaring him a bit before telling him he was just joking. You could tell from the Mayor's smile that he was quite satisfied.
The scene in the Town Hall where the Mayor thinks that maybe they should cancel the Who-Centennial. The Councilman presses a smiley button, a dome descends around the Mayor and the council, and Muzak begins playing, causing the panicked Whos to relax. As this is happening, the Councilman is chasing the Mayor around the dome. In the next shot, he's strangling the Mayor. And then the next shot shows him pointing first to the Mayor and then to a picture of a donkey. Probably not too hard to guess what the Councilman was calling the mayor.
"Oookay, Hor-ton - fake name - where are you?"
"Oh, voice from the drainpipe."
The first time you see Ned the Mayor. He's stirring his coffee, then he bends to pick up his newspaper and spills it all without noticing. He then goes to take a sip and looks adorably confused as to where his coffee has gone.
The deleted scenes show that the scene would have been extended. Ned finds his coffee landed into the wheelbarrow of a garden gnome, and tries to drink the coffee from out of it, getting him stares from his neighbor.
"I don't even remember. Yes, I do. BLAAAARGH - you know, some guy was talking to me... not an elephant in the sky. A guy on the ground."