This poll is rubbish, some of the best series ever made aren't included:
Firefly
Battlestar Galactica (the recent one, though the original is enjoyable in its own right)
Blakes Seven (Terry Nation's great gift to Sci-Fi)
Red Dwarf
Lost In Space
Terminator: Sarah Connor Chronicles
... and don't bundle series together, some in a family are better than others (Torchwood stands up on its own), and Star Wars has never been a series as such - though I used to enjoy Droids, and Ewoks when I was a kid...
I'd probably change my vote if the list was more comprehensive.