What is your favorite TV series of all time and why?

For instance, my favorite series is Farscape. It was a wonderful show that was never afraid to try something new. The characters were well written and acted. The use of puppets and CGI were fantastic. I mean, after a couple of episodes, you forget that Rygel was a puppet completely.

The villains were some of the best ever created. Crais's ultimate redemption had me proud and upset at the same time. Scorpius' cunning never let down and you never knew exactly where his loyalties lay. No one on the show was two dimensional. The some of the themes were presented were done in a way that no other show would dare come close.

So what about you guys, what show...any show? And please, don't just put the name of the show. That would just be boring.