I'm in season five of Gilmore Girls--so no spoilers please! But I've noticed something about the sort of hybrid structure of the episodes, somewhere between a true ensemble (like Friends or Lost) and being a more focused show (like Bewitched or Frasier).
Actually, you might read the next few paragraphs and say, "duh." I'm a little slow sometimes. But it's curious to me how a show like Gilmore Girls--or fine, even Frasier--can create a setting and then populate that with minor characters, most of whom aren't all that interesting/round. For instance, Gilmore Girls has a lot of people in the quirky town of Stars Hollow, and these people will pop up for a joke or a small subplot: Kirk is wackily interested in everything! Taylor is a terrible person, ha! Gypsy, uh, fixes cars?
But (ok, yes, much like Frasier) Gilmore Girls also invests in a number of other characters, all of whom could handle their own plots. Unsurprisingly, most of these characters are in the Gilmore family: grand-daughter Rory, daughter Lorelei, and grandparents Emily and Richard. So we can follow Lorelei dating in Stars Hollow and Emily's issues with her mother-in-law and Rory dating in college.
Which is interesting to me because Gilmore Girls seems to have succeeded in keeping interest past a life change in a way that many other shows falter with. So Buffy starts as a high school show and has a little trouble switching to college. But GG keeps a finger in so many worlds that a change to one doesn't throw the whole show out of balance. Rory goes off to college? Well, mom is still home. Lorelei opens a business? Well, her parents are still there, doing their rich people thing.
So by juggling these different characters in these different environments, the show has some robustness--a single misstep won't derail the whole thing. Even compared to Frasier, this is a pretty interesting feat. (I mean, when Frasier leaves radio for a while, doesn't the show founder a bit?)