Does Quantum Leap count?
It wasn’t REALLY a cliffhanger because they wrapped the story up…but it was convoluted at best because it was supposed to be a cliffhanger, then re-wrote it.
How about the best anti-cliffhanger…That one sitcom (name escapes me) that ended with the last breaking the fourth wall and just saying “Bye everybody!”. I don’t know what it is, but I saw that on “I love the (insert appropriate decade here)”.
Farscape. Damn, that one hurt. Not just a cliffhanger, but the two leads pulverized into cremains. 
The writers weren’t expecting cancellation, and had no time to even do that “cram the final two seasons into the last three episodes!” thing.
Of course, they did make it mostly better with a 4-hour miniseries special a couple of years later, but it wasn’t the same.
Can’t really count because it was never meant to be resolved. And anyone who says Tony didn’t get whacked is just kidding themselves. 
Showing my atrocious viewing habits, *Mortal Kombat: Conquest *ended with all the heros dead and Shao Kahn telling Rayden to bow to him.
That was one I neglected to bring up in my OP. Thanks.
The ending doesn’t make sense [to me] if he DOESN’T get whacked…
I’m drawing a blank on Joan of Arcadia but I’m pretty sure it’s a cliffhanger. If it isn’t, at the very least they set up a kick ass 3rd season.
Aww, geez. Did you really have to put a spoiler in the opening paragraph (and therefore the mouseover text)? That episode of Earl hasn’t screened here yet.
Besides Dallas, that other great primetime soap of the 80’s, Dynasty, also ended its run with a cliffhanger. Also the new *The Fugitive *series starring Tim Daly ended its one-year run with a cliffhanger. Too bad really.
John Doe on Fox ended with a pretty big cliffhanger. Years later, someone involved with the show spilled all the beans about how the show would’ve resolved everything had it continued, and I have to say, I frankly prefer it just ending on a cliffhanger.
What you’re talking about never happened.
Got it?
I’m sorry. I plead ignorance. I was totally unaware that “My Name Is Earl” aired Down Under. I know, that’s no excuse. The finale was less than two weeks ago and I should have considered that not everybody had seen it. Still, I never even once considered Australia. Again, I’m sorry.
Pretty much every “mystery” premise show has ended with unresolved mysteries. Pretender. Wonderfalls. Joan of Arcadia. Journeyman. And so forth. This is why I refuse to watch any more of them.
Veronica Mars ended as Veronica casts her vote for sheriff, an election whose resolution we never get to see.
Reaper fans will never find out if Sam escapes his contract with the Devil. (Actually, the “season” finale is tonight, but I’m doubting that they’ll wrap up anything.)
Hey, that’s ok. Thanks to the wonders of the internet, I’ve seen it now. 
The UPN (or was it the CW?) sitcom Half & Half ended with a cliffhanger about which of two suitors Rachel True’s character was going to pick. Now she’s in dating limbo forever.
Aw man, are they not renewing it? I stuck with it through the writer’s strike and I thought it improved about tenfold after they came off that hiatus. Too bad it’s gonna go.
This site says it is officially canceled. It has been pretty spot on in predicting and reporting since I started watching it. It was growing stale for me anyway. Sock was an overwhelming ass, Sam was supposed to be a “good guy” but for me was basically a sorry little wimp and Ben even more-so. The only interesting character was Satan.
Blake’s 7
and I’ll point out that Mortal Kombat had Jaime Pressly in a few episodes.
Except they also ended on a cliffhanger, something involving prophecies. It always bugged me because i REALLY WANTED TO KNOW! 