Man, I fucking love the Marx Brothers.
Granted there are still lots of incredibly great comedians out there today, but you just don't see too many truly multi-talented icons like this. It wasn't just the comedy, but the music and personalities too. Groucho is arguably history's fastest-thinking comedian. His wit was still sharp all the way up through his old age. Not a bad guitar player either. Chico's Italian accent might have been a bad one-trick-pony schtick, but it worked. Plus, he was amazing to watch on piano. And Harpo was, well, Harpo: great pantomime comedian, and also a great musician. Zeppo had his role as the straight man in the early movies too, so he was still a necessary part of that whole formula at times.
Although Duck Soup gets all the praise, I'd have to say that my favorite movie of theirs was Animals Crackers. I was pleased to find my high school was putting on a play adaptation of it. They did a great job, incorporating some parts from other movies too.

