Friends
Seinfeld
The Office (US)
Cheers
Mash
The Simpsons
Family Guy
30 Rock
The Cosby Show
South Park.
Joe
Everybody Loves Raymond
Seinfeld
The Office (US)
Mash
The Simpsons
Family Guy
Scrubs
Will and Grace
South Park
Married With Children
Delete Friends and sub Roseanne.
The original list only has 19 shows in it because Curb Your Enthusiasm is shown over two lines.
Of the shows listed my favourites would be:
Friends
Frasier
Seinfeld
WKRP
Cheers
Mash
though I haven’t watched MASH in a long time. Missing from the list for me: How I Met Your Mother, Corner Gas, Coupling (UK version), Yes, Prime Minister, and new entrant of The Big Bang Theory.
Roughly in order of preference:
Seinfeld
Roseanne (sub)
Friends
MAS*H
The Simpsons
Frasier
The Office (US)
Will and Grace
South Park
Arrested Development
If we’d been allowed more subs, I’d have stuck The Golden Girls, Mad About You, The Nanny (shoosh!) and Laverne & Shirley in there too.
Frasier
Seinfeld
WKRP
The Office (US)
Cheers
The Simpsons
Family Guy
Malcolm in The Middle
Arrested Development
South Park
The Simpsons
Arrested Development
The Office (US)
WKRP
Seinfeld
Cheers
Frasier
30 Rock
Curb Your Enthusiasm
Mary Tyler Moore Show
I think the source list is a little bit too modern. Mary Tyler Moore Show, Bob Newhart Show, Newhart, Taxi, Dick Van Dyke Show, All in the Family, The Honeymooners, Sanford and Son, The Monkees, Soap and Dobey Gillis deserve consideration because I think they are great. And, I Love Lucy, Threes Company, Gilligan’s Island, The Brady Bunch, Happy Days, Laverne and Shirley, Mork and Mindy and Perfect Strangers should be choices because lots of others did.
pat
Of that particular list-
Frasier (whose star Kelsey Grammar had a [non life-threatening] heart attack today)
WKRP
The Office (US)
Cheers
Mash
The Simpsons
Family Guy
Malcolm in The Middle
Arrested Development
30 Rock
My all time favorites would include several not on the list that would jettison some of those that are. (Barney Miller, Sanford & Son, All in the Family and Green Acres all come to mind.)
I’m going with:
Friends
Seinfeld
2 1/2 Men
The Office (US)
Cheers
The Simpsons
Scrubs
Curb Your Enthusiasm
30 Rock
South Park.
I couldn’t stand:
Everybody Loves Raymond
The Cosby Show
I’d have to toss in Futurama as a substitute, for either Friends or Cheers, but mostly because they ran for so damn long they kind of lost their appeal.
Friends
Frasier
Seinfeld
WKRP
Cheers
Mash
The Simpsons
Family Guy
Malcolm in The Middle
The Cosby Show
That’s the top ten from your twenty, in order of how they were listed in the OP.
If I could sub only one, it’d probably be:
Sports Night <–subbed for Friends
Frasier
Seinfeld
WKRP
Cheers
Mash
The Simpsons
Family Guy
Malcolm in The Middle
The Cosby Show
If I could sub as many as I wanted:
Sports Night
The Addams Family
Night Court
Taxi
WKRP
Mash
The Simpsons
Family Guy
Malcolm in The Middle
The Cosby Show
I can only come up with five from the posted list. The rest I either don’t like or have never seen:
Seinfeld
The Simpsons
Family Guy
Malcolm in The Middle
South Park
Alas, I cannot sub just one:
Newsradio
Corner Gas
Futurama
King of the Hill
The IT Crowd (not as much as the other ones, but I honestly couldn’t think of a tenth)
Wow. Seriously?
Frasier
Everybody Loves Raymond
Seinfeld
Cheers
Mash
Will and Grace
These are the only ones I have watched with any regularity.
Friends
Mash
The Simpsons
Family Guy
Scrubs
South Park.
Those are the only ones I really have watched, the others I just don’t care for.
In order though:
Scrubs
Simpsons
SouthPark
FamilyGuy
Friends
Mash
Friends
Frasier
2 1/2 Men
Mash
The Simpsons
Family Guy
The Cosby Show
South Park.
WKRP
Everybody Loves Raymond
26 year old male:
Robot Chicken (Cartoon Network, Adult Swim)
The Office (US)
Everyone loves Raymond
2 1/2 men
SIMPSONS (It deserves caps)
Family Guy
Malcolm in the Middle
Beavis and Butthead
South Park
Scrubs
Married w/ Children (Not on the list, but I LOVED that show as a kid, and I still love it when I catch it on FX)
and Cheers (but that makes 11) 
My list, in order of the OP:
Friends
Frasier
Seinfeld
2 1/2 Men
Cheers
The Simpsons
Family Guy
Scrubs
Futurama <- subbed for The Cosby Show
South Park.
Friends
Frasier
The Office (US)
The Simpsons
Family Guy
Arrested Development
Scrubs
30 Rock
The Cosby Show
South Park.
I’m 50 and I watched many of the shows you listed during their prime time runs and I agree that some were very funny, but I didn’t go back that far since I only listed the first 19 that came to mind as I was writing the OP. Barney Miller, Fish, A Different World… there are many funny shows not listed.
If people are listing shows like Gilligans Island, then Petticoat Junction, My Mother The Car, The Mother’s In Law and shows like this would have to be included too. Gilligan’s Island? Wow!
Friends
Seinfeld
The Office (US)
Mash
The Simpsons
Family Guy
Arrested Development
30 Rock
South Park
sub: My Name is Earl
I don’t have DVR and most years I haven’t had cable and/or worked at night, so most shows I’ve only watched by default depending on what reruns are on (Seinfeld, Friends) or I went out of my way to get on DVD (Arrested Development). I haven’t voluntarily watched MASH in years but I loved it as a kid, and I have only caught a couple of episodes of 30 Rock, but I love what I’ve seen.
I loved WKRP as a kid too, but it has been so long since I’ve seen an episode I can’t include it, in case it is not nearly as funny as I remember.
I only ever regularly watched:
Everybody Loves Raymond
Seinfeld
Cheers
Mash
The Simpsons
Family Guy
Scrubs
Curb Your Enthusiasm
I never got into (maybe due to scheduling?) but quite admired whenever I saw them:
Frazier
Malcom in the Middle
the rest I watched once or twice and disliked.