Time to lay the cards on the table. I can't put them in order, that's like choosing between my children.
Remember, these are shows that you can watch over and over, have aged well, no cringey episodes, no characters that 'do your head in' etc. Minimum two series, nice mix between UK and US shows.
Blackadder (tough one as I cannot watch Series 1 for the life of me).
The Office (UK)
Seinfeld
Curb your Enthusiasm
Fawlty Towers
Family Guy
Friends
Friday Night Dinner
Modern Family
Extras