Carnivale. There was a lot left to tell and I found the setting/characters totally fascinating.
And I want one episode (fuck, I would take a ten minute webisode) to resurrect Xena: Warrior Princess because the way it ended really, really pissed me off. Killing off your main characters is bad m'kay, it makes those who followed a show, bought the DVDs etc feel really fucking betrayed.
I could just as easily said Blake's Seven (a classic 70s sci fi show), or Sapphire and Steel, or Quantum Leap. Dammit I want a happy fucking ending or what was the point to bothering with a single moment of emotional investment. Pro-tip to TV show developers/creators - if you keep doing it, people will learn to stop giving a fuck about your stories because we will have been taught that there is no bloody point because everyone dies at the end.
Grrr