Star Wars for me! I loved firefly and watched Battlestar Galactica religiously as a kid but I still think my midiclorean count would have high enough if I was tested as a child to go to the Jedi temple
Have to agree another vote for Babylon 5. It was one of the first Sci-fi shows to have a proper linier storyline and even managed to link a later episode to one far earlier without it looking weird.