Where to start and stop watching various TV series

The thread on the X-Files has prompted me to set up a clearinghouse of inside information on when good shows jumped the shark, and in some cases when good shows finally became good. We’ve been watching TV in a very “internet” way lately, picking up a series we like (often an old one), watching all of it in a row, then moving to another show. So this kind of information would be very useful.

My contributions:

Parks and Recreation - start watching with Season 2, Episode 1, “Pawnee Zoo.” I hear tell this is when the show found its legs, and it happens to be when I started watching, and I’ve loved it ever since.

**Heroes **- start at the beginning, and watch through the closing narration of Season 1, Episode 23, “How to Stop an Exploding Man.” Turn it off before the teaser for the next season begins.

**Farscape **- I was totally addicted to this show when it was airing, but recently my husband rewatched the whole series, and it seemed to me that pretty much everything after the first season is rather bad, compared to those first shows. Help delineating the exact shark-jumping moment would be appreciated here.

Criminal Minds-When Paget Brewster replaced Lola Guadino

That 70s Show - Start with the wonderful pilot, but stop after the sixth season.

I started a thread that’s very similar to this one that you might find helpful.

We’ve done this thread a few times and I’ll give my regular example. Twin Peaks. Start at the beginning. Stop when you find out who killed Laura Palmer. The entire show is only two seasons long so you might as well finish it out. It’s one of the best shows ever put on TV, but even David Lynch will tell you it declined after the reveal.

The Office (US). Opinions vary on when to start. I feel that you should start at the beginning and just sort of deal with the first half season. It’s awkward, but that’s really what the show is about. Stop when the Michael Scott Paper Co. is formed. It’s really all downhill from there.
You can keep going for another season or two if you want. If you stay on until Robert California shows up, you’ll just be watching due to momentum at that point. But if you to know when it went from “This really is a good show” to “it’s okay” it’s at some point during the few episodes when Michael had his own company.

To clarify: this is when you should start watching. IMO