Buffy was never a ratings success or ever considered to be "big thing" in television. It was very much a cult favorite and alhough it had good critical reviews, it had a pretty small and select audience.

That being said, I love serialized shows. The investment you put into the show and to the characters usually pays off in a much better way than with sitcoms or stand alone shows such as CSI.

I'm currently hooked on multiple HBO shows. Rome, Weeds, Big Love, etc. I like Heroes but that loooong hiatus really made me lose interest. As for Lost... poor Lost, I think I've given up on that show. I keep watching, but I watch it with a sort of pity toward what it has become.