I'm not much of a "TV series" watcher. Most of them are extremely shallow or violent or forced funny. The very few I have really enjoyed over the years are MASH, TAXI, and Northern Exposure. That's not many, in over 40 years of viewing.
All 3 of the series I've enjoyed have common threads - they are set in unique locations, have a broad array of quirky characters, are extremely well-written and acted, are genuinely funny in just the right places, and most of all, leave you with a really genuine "message" about life and relationships. Without fail.
Of the 3 I mention, Northern Exposure is the best, in my opinion. My favorite is the episode where Maggie and Maurice go half-and-half to buy and build a small airplane, have a falling out that ends up just perfect, and the final scene, with the airplane flying during the funeral was so emotional that it brings tears to my eyes every time I see it.
Unfortunately, when Rob Morrow left the show, it was never the same. I suspect the same would have happened if any of the 5 or 6 key characters had departed. After 5 years it was probably time anyway. But it lives on via DVD sets.
In a completely unexpected way I was able to meet Barry Corbin who created the memorable character Maurice. He was in the cast of a TV movie called "A Face To Kill for", being filmed near my home in August of 1998. My wife and I were extras for a week at the horse track and during the set up for an inside scene Corbin sat with me at a small table. We chatted for a couple of minutes as the sound man got things sorted, he was very gracious and kind. So I have an extra special memory of "Northern Exposure."
Update January 2024: The seasons are now available streaming on Prime, I have been enjoying re-watching them from season one, episode one. It is like seeing old friends after a long absence.