I don’t really think you could say that Kim Possible died early. It got to 65 episodes, just like all of the Disney Channel shows before Disney pulled the plug. (65 is the standard number for the shows, since with that many, you can show a show 5 days a week for 13 weeks without going into repeats, I think.)
I miss Wonderfalls I miss Remember WENN
I’d add Frank’s Place to that list. And (though it doesn’t begin with “F”) Brooklyn Bridge. Also Class of '96, which was supposed to follow a group of students through four years of college but never even achieved sophomore status.
Stark Raving Mad
I’d almost say The Lone Gunmen, but to tell the truth, I thought it had some serious flaws in it’s execution. Coulda been a lot better. (Their last appearance on X-Files, of course, was just too jaw-droppingly awful for words. Aside from the fact that I could almost feel Chris Carter trying to jab his thumb in my eye while I watched it.)
My all-time #1 would be The PJ’s. Wickedly funny, intelligent, and edgy enough to be “politically incorrect” without getting insufferably obnoxious. I never understood the silly flaps about it being offensive.
Got shuffled around to death and eventually just plain faded away. Never figured out what the hell happened.
I think Herman’s Head could’ve easily gone another season, maybe two. It was one of the most consistently entertaining Fox programs I’ve ever seen, and the acting all-around was fine.
Duckman, ah, undoubtedly the most underrated “adult”-themed cartoon ever. Definitely should’ve at least wrapped up the wedding arc before pulling the plug, for crying out loud.
And an honorable mention for Forever Eden. Just to see if anyone would ever figure out that all you had to do was be friendly and polite and decent and fun to be around, and you could continue living in a beautiful, luxurious paradise and getting paid for it. 
Clerks- They got 6 episodes and then the idiots in charge of the network decided to show 2 of them, out of order, and againest shows on other channels that were gureenteed huge audiences.
Invader Zim- The show deserved more then 1 1/2 seasons. It at least deserved to finish the 2nd season.
Newsradio, Newsradio, Newsradio!
Many will say it “died” when Phil Hartman died, but the cast and the writing was so excellent, they could have gone longer. I knows it.
Took FOREVER to get on DVD, too.
“Profit” created by David Greenwalt got totally shafted as did “Birds of Prey”
I’m going to nominate Nero Wolfe, running a very brief two seasons on A&E. Great acting and writing, too expensive to produce.
I forgot Clone High, The Critic, *Undergrads[i/], and Clerks.
Bosom Buddies–Just look at the cast.
Not to hijack the thread, but have there been any rumors of bringing it back if this movie is successful?
I thought Andy Richter Controls the Universe was a great show that died before its time.
I still miss My So-Called Life.
No love for Undeclared? It had such promise.
Damn you, FOX, with your serial show killing spree 
I was just coming in here to say that, dasgupta. I loved that show.
I miss the true televised joy that was Sledge Hammer.
I agree with you on Sports Night. The irony of it all was that inside the show, they had just gotten renewed after weeks of thinking they were all going to be out of a job.
Fox gets a lot of flak (deservedly so) for cancelling good shows, but I think it’s mitigated quite a bit by their campaign for Arrested Devlopment. Nobody’s watching it, yet it’s lasted two seasons, and it’s coming back for a third. Fox is also rerunning the show at midnight and in blocks on Fridays in order to drum up interest. In another life, AD would be a prime candidate for this OP.
Not having watched it religiously, but still being intrigued, what was it?
-Joe