Comedy
Testees - was off the chart funny but FX never picked it up for a second season. Not for the kiddies.
Reaper - excellent modern slapstick
Never given the chance they deserved.
Defying Gravity - Top notch Sci-fi with a great cast, but panned by all of the critics for being and empty shell. I guess they never bothered with more then one show. Amazing potential!
Firefly - Set to be a top notch Sci-Fi adventure also with a great cast.
Journeyman and
New Amsterdam came and went in the same season. Both great stories with great potential.
Urban Fantasy
Dresden Files - Good news is I was able to find the book series which just got better with each new novel.
Blood Ties - I also found this series of books not as good as the Dresden Files but quite an enjoyable read.
Left Hanging - shame on them.
Terminator : The Sarah Connor Chronicles - Just when it was starting to roll it gets canceled. Fox ends up with some great shows that they are just short sighted on and get canceled before they should.
Rushed Conclusions to avoid irate fans. You can watch either Jericho or Dark Angel and at least know there is going to be some sort of conclusion at the end of your viewing.
Jericho - Canceled then brought back for a seven episode conclusion to avoid the execs being buried in nuts. 20 tons were sent in to the network to protest leaving the series high and dry.
Dark Angel - An excellent concept that dealt with the northwest after an EMP bomb explodes and burns out most all modern electronics in most of the US.
Never finished properly.
The Pretender - An excellent series that never had the true conclusion the fans deserved.