The thing that I struggle with when it comes to a defining title is that a lot of these comics did multiple recurring genres that could be their own group. I may have to play with this a bit.
The Three Stooges: Going to go with A-PLUMBING WE WILL GO. While I do find DISORDER IN THE COURT to be the best, it plays out almost like a stage production. PLUMBING feels more like a typical Stooges short - but the epitome of that. For the Shemp era, BRIDELESS GROOM takes my vote.
Laurel And Hardy: Tough choice between THE MUSIC BOX and HELPMATES. But I'm probably going to lean towards the former. Part of the fun of Laurel and Hardy's films are the bizarre characters they come across, and Billy Gilbert's short-tempered professor takes the cake. Feature is a toss-up between SONS OF THE DESERT (the best of the 'Laurel & Hardy Vs. the Wives' films) and WAY OUT WEST. BLOCK-HEADS just barely inches behind but I mainly focus on the reunion scene as a "defining" moment. THE DEVIL'S BROTHER tops in the Operetta category. I'll add BIG BUSINESS as a defining silent short. A small issue builds into total chaos. Plus, it's got Jimmy Finlayson getting in on the fun.
Abbott And Costello: In terms of the horror comedies, MEET FRANKENSTEIN easily wins top slot, though HOLD THAT GHOST isn't far behind. I'd add BUCK PRIVATES as a top tier non-horror comedy. It's a great introduction to the team, with everything feeling fresh and new, and the guys displaying a high energy that wouldn't always show up later down the road.
The Bowery Boys: Once again, I find myself splitting things up into 'horror' and 'not horror.' For the former, probably going to say THE BOWERY BOYS MEET THE MONSTERS - just a fun takeoff on the B-horror genre. MASTER MINDS isn't far behind, though. BLUES BUSTERS takes my vote as the best non-horror BB flick. It was easily the most creative use of the 'Sach Gets a Superpower' formula, and it even has some heartfelt moments in it. I'm tempted to add a category for service comedies (for which I'd say the gag-packed LET'S GO NAVY!), and I'm really tempted to throw in the criminally underrated BLONDE DYNAMITE as a great introduction to the characters...
Martin and Lewis: The most part, I feel the M&L movies didn't really show the team off properly, often splitting them up. THE COLGATE COMEDY HOURS are where we really get to see them shine. For the movies, ARTISTS AND MODELS is a rare exception.
Little Rascals: From the silent era, I'm going to say either THE CHAMPEEN! or DOGS OF WAR! For the early sound years, TEACHER'S PET, DOGS IS DOGS, FREE WHEELING, or HI'-NEIGHBOR!. For later 'Alfalfa' years, DIVOT DIGGERS, HEARTS ARE THUMPS, NIGHT 'N' GALES, FISHY TALES, or any of the FOLLIES shorts.
Marx Brothers: Either HORSE FEATHERS or ANIMAL CRACKERS.
W.C. Fields: IT'S A GIFT and THE BANK DICK.