Showed Sherlock Jr. to some kids and they just loved it. Used to be a fan of Chaplin--loved Gold Rush, and City Lights, but only the early parts of Modern Times (the latter half wasn't as funny, they thought).
Then I started them on Keaton, and they promptly forgot all about Chaplin. The General, first, which I thought would be a tough act to follow, but The Navigator they found even funnier.
Our Hospitality was a bit dull till the final stunt (funny, I loved it when I first saw it), but Sherlock Jr. topped everything. Kids who have seen the Lord of the Rings movies and could hardly sit thru Attack of the Clones, enthralled at the sight of Keaton walking into a movie screen, or diving through a man's midriff.
In terms of Keaton's works, I suppose it's hard to choose a favorite, but off the top of my head and please no one hold me to this, I'd say The General was his most perfectly structured and beautifully shot work (the shot of him chopping wood while the entire Civil War passed by behind isn't just irreducibly funny, it's a lyrical piece of cinema; Lean must have tried to emulate the shot of the train on the collapsing bridge for Bridge on the River Kwai--not very well, in my opinion), The Navigator perhaps his funniest, and Sherlock Jr. his best filmmaking--and some of the greatest filmmaking I've ever seen.