...I'm still going with an ongoing that ended. Seems there's a point where you have to acknowledge a series as going on for such a long time. My semantics are superior.
The definition of a limited series according to Dark Horse Comics: "a comic book series with a clear beginning, middle and end." When a limited series ends, it ends because the writer of the story has decided that the story is over. Some of these books last for a very short time (such as the four issue The Dark Knight Returns) and some of them last for a very long time (such as the 52 issue 52, Countdown, and Trinity).
The definition of an ongoing series is a comic book series that is intended to go on for an undetermined amount of time. Because of this we see books like the Amazing Spider-Man, Wonder Woman, the Incredible Hulk, and Thor reach 600 issues, books like Batman and Superman reach 700 issues, books like Detective Comics reach 800 issues, and books like Action Comics reach 900 issues. When an ongoing series ends, it is usually because of low sales (Doctor Voodoo, Blue Beetle, Manhunter), creative/editorial decisions to take the character/team in a new direction (Green Lantern, JLA, the Flash, New Avengers), production problems (Grant Morrison's WildC.A.T.S. and the Authority), or reasons that are not the result of the original creator having a definitive end for the story.
Wolverine: Origins did not end because of low sales, creative/editorial decisions to take Wolverine in a new direction, production problems, or whatnot. Wolverine: Origins ended because Daniel Way had a 50 issue story that had a set begining, middle, and end about Wolverine's struggle against Romulus and confronting his misguided son Daken. It was always meant to be a 50 issue series, no more, no less. Therefore, it falls under the definition of a limited series. And since it was over 12 issues, it falls under the definition of a maxi-series. Yeah, Marvel treated it is if it were an ongoing, because it was a book that went on for over four years and had a spin-off series with Dark Wolverine. But it really wasn't.