Alphas - 2 seasons - cancelled. not wrapped up. sigh…
Six Feet Under, Ended and all wrapped up with a nice little bow, couldn’t have asked for a better ending.
The OP didn’t express interest in Kidnapped or Terriers, but both shows are excellent.
Kidnapped wrapped up the first season mystery. I suspect subsequent seasons would have had different victims for Jeremy Sisto to rescue (or not). Terriers was open-ended but only in a where-will-they-go-next kind of way.
Kidnapped needs more love. It was marvelously twisty with well-drawn characters, both the good guys and the bad guys.
wondering about a few on my current list…
Ghost Whisperer - 5 seasons - ?
Buffy - 7 seasons - ?
I’m thinking both were planned exits judging just by the number of seasons they ran, but like i explained in the op, difficult to research spoiler free…
nobody seems to know about Jeremiah. By that, I’m guessing it was probably axed… haha
a few that can be added to the inventory:
Star Trek: TNG - 7 seasons - planned end, storylines wrapped up
Star Trek: Voyager - 7 seasons - planned end, storylines wrapped up
Enterprise - 4 seasons - cancelled - mini-arc wrapped up, series hastily wrapped up in last episode (if memory serves)
Babylon 5 - 5 seasons - last minute renewed past 4th season planned wrap up. wraps up again at end of season 5 (again, if memory serves)
Back in 2006 a show named Runaway was on the CW station to me it was nothing but edge of your seat suspense, but because it was cancelled after just three episodes, no one ever found out how things were going to go for the family that the show was about. 
God bless you always!!! 
Holly
Supernatural - Yes it’s still on, but the original arc wrapped up quite nicely in season 5. Seasons 6 onwards are like a sequel. Even if something happens and that doesn’t get wrapped up, it’s still worth the first 5 seasons at least.
Not that I really recommend watching either show, but two recent shows I watched:
Terra Nova: cancelled/not renewed, season kinda wrapped up, but major plot lines and cliffhangers unresolved
Last Resort: cancelled/not renewed, wrapped up (though it’s obvious several plotlines get heavily truncated; the last episode is about half normal season-ender and then half every-plot-line-gets-ended)
Buffy - 7 seasons - wrapped up
The Chicago Code: Not a popular show and it was cancelled after a single season. But they did manage to give its main story some closure in its final episode. And they did it in a way that left them enough wiggle room to reopen the story if they had been renewed.
Gilligan’s Island. They followed up with a couple of TV movies, but it was too late.
The Bob Newhart Show would have been a candidate, but they wrapped it up years later at the end of Newhart.
Clone High: Cancelled after a single season. Ended with a cliff-hanger that was supposed to be resolved in the second season opener.
My Name Is Earl: Greg Garcia knew the ratings had declined in the show’s fourth season and there was talk of cancellation. So he approached the network and offered to write a series finale, which would wrap up the main story. But the network said they were going to renew the show, so Garcia ended the fourth season with a cliffhanger to bring people back for the fifth season opener. And then NBC decided to cancel the series anyway.
Garcia has made references to characters from My Name is Earl in his subsequent series Raising Hope.
addendum to the *Babylon 5 *entry (for completists):
There were multiple stand-alone full length movies made after the series concluded.
Also the spinoff Crusade - which lasted only a 1/2 season before being cancelled. obviously no wrapping up, they barely unwrapped to begin with.
it’s also worth mentioning that most British TV series are planned, limited run affairs - that wrap up (at least as much as the creators intended). The Prisoner comes to mind with it’s 17 episodes. Any exceptions to this general rule? Doctor Who of course would be an exception, but that’s just because it’ll go on forever! Any shows actually cancelled worth mentioning?
If memory serves, I thought the ending of Stargate: Universe was satisfactory.
My memory remembers it differently…
I seem to remember it was left open whether everyone was going to live or die - with Eli running the ship by himself, hoping they would make it to the next galaxy
*Stargate: Universe *- 2 seasons - cancelled, not wrapped up
Stargate: SG1 - 10 seasons + 2 movies - wrapped up
Stargate: Atlantis - 5 seasons - wrapped up (albeit maybe a little hastily)
Good old Space: Above and Beyond. Writers found out it was going to be cancelled, so went out with sort of a bang.
Gene Roddenberry’s Andromeda - 5 seasons - (i think) a planned ending, all wrapped up
Yogurt, I raise your Space:Above&Beyond one Earth 2!
Earth 2 - 1 season - cancelled. don’t remember any closure
Even so, I think it ended in a decent place. There was wiggle room, but it felt satisfactory to me.
I thought that the ending to Stargate: Universe was fitting, in an odd way.