I guess Simpsons is the best ever for me, as it's still running.
Past shows... maybe x-files. I mostly watch scifi, fantasy, adventure stuff. Drama series don't interest me much, except shows like "Six Feet Under", "Queer as Folk (UK version)" and such (maybe just because they have gay characters
). Also I quite like british sitcom comedy: Absolutely Fabulous, Coupling (I hope they re-run, I missed it almost totally on previous run(s). Of US sitcoms I've recently watched only Friends and W&G.
I was watching Buffy a couple of years ago, but then they changed the showtime to something that I tended to always miss. This left me with a gap of a season plus some episodes. Now it is airing on sunday evenings, and I've started to watch it again. This is one series I've considered buying on DVD to see the episodes I missed in between.
I'm not a huge fan of any series, I don't yet own any episodes on DVD.
I'm really much of a TV-series type. There's maybe two or three series I follow at one time, and from them maybe one I try not to miss.
But maybe that's just telling more of the quality of series running on finnish TV network than anyhting.
Still, there are many series I'd like to follow, or would have liked to folow, but only manage to see them occasionally. Like "Freescape", "Alias", "Firefly"(not running here anymore, missed a couple of episodes), Sopranos, Angel...
I'm looking forward that they'd show "The Lost" here soon, that might become my next "must see series".
Edit: Oh, and of course "Sex and The City" (I'm Charlotte
)