Too many to choose from.
Seinfeld is the only no-doubter for me.
If cartoons are in play then Family Guy gets in (due in part to recency bias).
The Honeymooners gets my non recency bias vote.
And I'll put Cheers on the mountain - at the expense of other great choices like Barney Miller, Taxi, Munsters, The Office...I could go on and on.
Nice to see My Name is Earl mentioned by @T&C . And I'd also put shows like Soap and Scrubs in the same category - loved them all but they fell just shy of greatness for me.