I just watched an episode of Frasier that's right up there for me. The "Nightmare Inn" show where Frasier stages a retro radio mystery is pretty classic.
"Look out, he's got a NUG" from Bulldog's vaguely attractive dyslexic girlfriend is a nice touch.
That's one of the very few shows (Breaking Bad, Saul) that maintained quality and consistency for its entire run. It didn't dive off the cliff in the later seasons (Sopranos) and become almost a parody of itself. The writers were fantastic and found ways to beat the same drum over and over and over, but always with a slightly different and humorous beat. The casting was also stellar. Roz, Daphne, Martin, Bulldog, Gil, and particularly Niles were all perfect.