I realize that TNG is a show that's been off the air for 16 years now, and their run in the theatres is done now as well. Nevertheless, I have a good reason for talking about this classic show.
TNG is a perfect show. I mean, it has a LOT going for it to support this claim. I'm going to go through some of them.
1) Episode Quality Goes UP rather than DOWN
Most shows these days tend to be really well written right out of the gate, but eventually falter as the show goes on. This only makes sense - there's a lot of pressure on show runners to get their series picked up by networks, and then loved by audiences. For the most part, the writers seem to push out the quality stuff from the get-go, and then the super awesome creativity eventually wanes.
TNG had the advantage that they knew they were going to last. I mean yeah, the original Trek was cancelled, but TNG came into existence based on strong fan support. No one was going to cancel TNG - so the show had the opportunity to test the waters and make mistakes (and boy, did they make mistakes!). They got most of their kinks out, and we had 7 great years of Trek. There were even some really great shows in the first two seasons, and this was despite a 1988 writers' strike!
2) We love the characters
While TNG was episodic in nature, it was very much a show about the relationship between the characters. We watched them grow from season to season and learned about what makes them tick. This is what Deep Space Nine improved upon later, incidentally, which is part of what makes DS9 my favourite Trek series of all-time.
We love to laugh at Data's antics in his quest to become human (fun fact: did you know that in The Schizoid Man, there was a cut scene where Data imitates Picard's bald head?). We love it when Troi's mom makes passes on Picard, and in one episode forces him to proclaim his undying love for her, thus making him uber uncomfortable. Some people might even have shed a tear when Worf was discommendated - I don't know.
The point is, the show made us care about what happens to these characters, even if we knew they were ultimately going to be safe at the end of the episode.
3) We can watch the episodes over and over again
This really speaks about the quality of the episodes again - that they're good enough to watch them over and over. It's like Seinfeld (almost) - no matter how many times you watch the episode, you can always come back for more. The reason I mention the "replayability" is because there are a lot of GOOD shows out there that are just simply unwatchable to me after I've seen them.
Take Dexter for example. I've seen all 4 available seasons now, and for a time I considered purchasing it on DVD. But then I realized that I don't want to watch them over again - the nature of the show makes it hard to just sit down and watch a show. I think the difference here is that Dexter has a focused timeline that it's following - all episodes build on the previous show.
Whereas TNG, while all episodes happen in the same universe and are sometimes referenced, stand alone. You can watch an episode of TNG and not know anything about what happened in previous seasons, and you'd be fine. Well, except for the episode "Family" which directly references "The Best of Both Worlds". But that doesn't count.
Those are just three reasons why I keep going back for more TNG. And three reasons why I think it is the perfect show. I have yet to find a show that measures up in the same way - Deep Space Nine is a close second; Voyager has too many flaws to be considered; the closest I've found is Stargate Atlantis, and I'm still on the fence about that one.