If you're like us, you know the excitement that comes with discovering a great new TV show -- even if it means shunning human contact for a few days while marathoning it from Episode 1 in order to catch up with what's on the air. It can be a drag, though, to learn that the new series you've found isn't actually on anymore -- or, in the case of too many sci-fi shows, has been canceled before its time. That's why this roundup of our favorites only includes those that are still going strong.
