You people sure like Firefly! I've never seen it myself so I can't really say much about it.
I have a list of things I want back on air or at least something in webisodes or like that. Here it goes(In order of "I NEED THIS TO KEEP ON LIVING":
-The Black Donnellys: I read a couple of this 10 pages long thread in search of it and my efforts were fruitless(Got sick of reading "Firefly" come up all the time, though). I loved that series; it had it all: Drama, humor, action, blood, the good brother and the bad brother. Great writing too, but somehow it didn't appeal to the masses so it sadly got cancelled in the first season and ending with the most insulting cliffhanger I've ever seen.
-The Good Guys: Awesome old school police comedy show. It had over-the-top shootings, over-the-top car chase scenes and all that stuff. And it was great... But since every episode had a different plot with not much correlation between episodes it didn't end in a cliffhanger... But still, I miss it.
-Traveler: When I heard the premise a while back I was thrilled, but I never got around to watch it. Years later I decided to look it up and watched the whole first season. It was ok, it had its highs and lows but the thing that pisses me off it's that the directors of the show knew it was going to be cancelled and STILL ended the series with a cliffhanger...
-Joh Doe: I used to watch this with my sister. I thought it was the coolest thing ever and really enjoyed the premise of a person that knew everything except his name. Then the series hit a cliffhanger and then they stopped broadcasting it, with occasionally reruns at 4pm in the afternoon.
The worst thing of all things is that I get this series a tad late in my country, so when I start to get hooked up I find that it is already cancelled and I hate myself for getting hooked up.
That being said, I could add Invader Zim just for the lulz.