I always thought it was a shame they cut so much of this dance scene out of the final film, but I'm a big fan of dance.
UPDATE: Unfortunately, this video doesn't include one of my favorite quotes from the film, to wit:
Scarecrow: I haven't got a brain... only straw.
Dorothy: How can you talk if you haven't got a brain?
Scarecrow: I don't know... But some people without brains do an awful lot of talking... don't they?
Dorothy: Yes, I guess you're right.