I noticed in the Top 15 Shows That Never Won A Comedy or Drama Series Emmy thread that a few of them never even got nominated. Examples:
Buffy the Vampire Slayer
Veronica Mars (even after the rules were tweaked to make it easier for that show to get nominated)
I cannot believe that show was never nominated. One of the biggest series snubs in Emmy history!
Parenthood and Brothers and Sisters come to mind
Easy choices for comedy and drama….
Gilmore Girls & The Wire
Hmm, for Drama, the list of series that were post-pilot Drama Writing nominees but missed Drama is a pretty high-caliber one; last 50 years:
Homicide Life on the Street