My favourite anime gag probably comes from Azumanga. As for Cro, I think it's when the rival school gang boss, closet comedy guy, beats up the other guy for saying 'his' joke, and someone says: "Told you, he hates jokes!"
yeah thats funny very difficult to choose a gag in cromartie.
I saw Azumanga, and is really funny but the closest to Cromartie I've ever seen is Dragon Half. In fact I'm going to make a recommendation right now.
For me the best gag in Dragon half is the one of the ticket "if you saw DH you know what I'm talking about"
I've seen DH not so long ago and found it plain funny. Sure, it's no match for Cro, anyway :) But what is a match? The clash of delinquent pathos and absurdity of the universe makes the show seem pretty much unique to me. It's very different.
Okay, I rewatched Azu and I think I can name three gags, I can't say which is best in my eyes.
About 37% of my heart go to the episode 7 scene, where Osaka tries to sell her stuffed toys to a girl during the school festival (of two little shapless pillows one turns out to represent a tower in Osaka city, the other - Hanshin prefecture).
About 30% stand for Sakake's imagery of Chio-chan's "Father" (the big yellow cat pillow-toy) as Santa Claus in episode 17 ("All expences are covered by government! - Sugoi! - And I can fly at 100 Mach! - Sugoi, sugoi!").
The rest 33% belong to the unforgetable scene in episode 22: knife-wielding Osaka awakens Yukari-sensei ("Ah, you're up already... I couldn't make it...").