Northern Exposure
Buffy The Vampire Slayer
The Good Life (British - known as Good Neighbours in U.S.)
Oh, geez, you had to bring in English shows. I hadn't even considered them; they're almost a whole different thing.
Monty Python's Flying Circus is in a class of its own. I've seen the whole series on TV at least 4 or 5 times and have been through the DVD's at least twice. Some of the skits get funnier every viewing.
Agree with you on The Good Life -- I've seen that whole series multiple times and seen the DVDs multiple times (except the last one which doesn't play).
The Fall and Rise of Reginald Perrin. I'm still pissed that Leonard Rossiter died young. He was a genius. Ditto watching the shows and owning the DVDs.
(Ditto Jeeves and Wooster. When House first came on I couldn't watch it because every time I tried, I was seeing Bertie instead of House and couldn't stop cracking up.)