Big Rod = Roddy McDowell. No one who appreciates Bookworm can have all-bad taste.
Oh, okay. I get you now.
That actually might be my favorite episode of ***Batman ***ever. I’m pretty sure it was the first one I saw in color, over at a friend’s house. I liked the way one minute was stretched into five outside Big Benjamin.
The episode of Family Guy where Stewie shakes down Brian for a gambling debt. Unbelievably violent, but funny as hell! 
Twilight Zone - that cornfield episode, It’s A Good Life.
You’re a bad man, Ukulele Ike.
Good call. Ironic and gut-wrenching at the same time.
Speaking of Noah Hawley, the second season of Legion was also brilliant but I’d flag the episode with the various alternate realities as a standout. The last episode was also awesome but mostly as the culmination of all the story arcs of the season (apart from the opening fight scene, which was excellent).
For Supernatural, I’d say more:
http://www.supernaturalwiki.com/6.15_The_French_Mistake
The episode where they are thrown into our reality, and treated like actors in the show.
God, I miss when Supernatural was funny (ok, not seen last two seasons).
The Big Bang Theory: The Adhesive Duck Definiciency
Both of the storylines are superb. The interplay between Penny and Sheldon culminating in the funniest rendition of “soft kitty”. The rest of the gang in the desert, back when Howard was single and horny and funny, and the line “I hate my name - it has nerd in it”.
Fawlty Towers: Communication Problems
It had been four years since the first six episodes. Anticipation was very, very high. Could the second series possibly be as funny? Oh yes. And then some.
Another one of my personal favorites that probably doesn’t objectively belong in a “greatest ever” discussion, but still:
Angel S5E14: Smile Time
Who’s a cute widdle puppet?
My two top favorites are the initial episode, which showed you the premise, Arrival and the episode Hammer into Anvil, in which Number Six really shows what he can do. But Chimes of Big Ben is one of my favorites, too.
Omigod. Too too many. Just three?
My number one remains “Edith’s Birthday” from “All in the Family”. The most intense sitcom episode about a serious subject ever made. And it managed to be funny too, without being offensive.
I have to include a Doctor Who episode, so I choose the fourth Doctor in “City of Death”. The Paris one with John Cleese. Perfection.
Third? I dunno. Do miniseries count? If so, “Roots”, the episode where Kizzy is sold away. Utterly wrenching to watch and unforgettable.
Nope, sorry for the confusion. I meant as many as you please. I only posted three in the OP because those were the three I had in mind when I created the thread.
A worthy candidate, but I’ll go with “Hizzoner the Penguin”/“Dizzoner the Penguin”:
Note to Chefguy and The_Peyote_Coyote: the WKRP in Cincinnati episode title is Turkeys Away, not *Turkey Drop.
*
LINK.
Linc.
That’s the one I came in to mention.
(I’ll add my own rolleyes to “Elaan of Troyius” This is literally the first time in fifty years of Trek fandom that I have ever heard that one held out as even one of the best TOS episodes, to say nothing of THE best.)
Maybe Dropo has a “thing” for France Nuyen. She was pretty hot! :o
I remember her from St Elsewhere, too. I think the episode of that series I remember best is the one where Shirley shoots Peter in the morgue. 
I first saw that probably during the first run of syndication in the early 00’s and I always remembered the ep name. But it was on during a marathon a couple of months ago and I had to bail pretty early, couldn’t take it.
I’d substitute “Kill Switch.”
Freaks and Geeks, being perfect in almost every way, has so many good moments and episodes. But the episode “Dead Dogs and Gym Teachers” stands out.
It has this classic scene with Bill Haverchuck relaxing with some quality alone time after school.
[Groucho]
And that’s a very painful place to get shot!
[/Groucho]
Sanford and Son:
“Mama’s Baby, Papa’s Maybe.”
“Fred Sanford, Legal Eagle.”
“Wine, Women & Aunt Esther”