Probably only rating this my favorite because I just finished it: The Tomorrow People. On Netflix streaming. Excellent show, and it deserves a higher rating. If you liked Jumper (the book and not the movie, which was mediocre, if watchable) you'll like it, though teleportation isn't the only power used.
There are a few of other shows that I liked that got canceled. A good number of them are from around the TV writers strike:
Traveler
Journeyman
Day Break
The Chicago Code
Moonlight
Firefly
Heroes (I don't care what everyone else says, even if the other seasons weren't as good as season one, it was still better than most other shows even after season one)
Tru Calling
The Loop
All of the shows were cancelled early. I don't mind as much if a show has time to wrap up, even if it's short lived, or if a longer-lived show ends with some finality. It's the shows that are killed off after mid-season cliffhangers or forced into shortened seasons early on that leave me wanting more.
If we're including shows that ended their run after a few seasons, it's a much longer list.