My all-time favorite finisher, INDY WISE only, is the Spinning Impaler. I've only seen it done by Derek Frazier in CZW, and it was probably, bar none, the most shocking thing I'd ever seen. Since then I've seen some cool stuff that is in it's league but it's still nuts. Unfortunately I haven't seen Frazier in a hella long time, outside his recent appearance at A Tangled Web which I assume was a one off showing. Still, his move lives on forever in awesome spot move history!
[video]http://youtu.be/aMg4NTbVoWg[/video]
There are better versions of it. But, honestly you had to have been watching it, not braced for the move, and in full motion to really appreciate the insanity of it, but still.
As far as mainstream finishers are concerned it's hard to hate the Perfect Plex, such an elegant, textbook move executed to perfection and almost almost meant defeat. I'll add the Scorpion Death Lock from Sting, Lariat from Stan Hansen, and the Muscle Buster from Joe to that list, just to name a few. Oh, and I'll go ahead and add the Death Valley Driver, originally by Papa Shango aka The Godfather, and then used for a short time by Rene Dupree.
Worst of all-time? I don't think there really is a worst, but my least favorite that's going would have to be D-Bry's leg-wrap guillotine. For a submission specialist and one of the most well versed technicians in the game, he does an awful job making that look like a move that would legit cause someone to tap out. He doesn't connect his arms is the main problem, and without connecting hand to wrist, or elbow even, it just looks like he's holding someone in place. I hate to shit on Bryan in any case, but I'm just being honest. One of my least favorite of all time, I'd say, would be the reverse STO, by any lowercard WWE wrestler in the past decade. They handed that finisher out to about four people in the span of the decade, none of which had any momentum, and it was used to death and became generally useless. I got sick of seeing jobbers use it. So, that's that.