I have a fondness for movie 'twists' even if they have become overrused and something of a cliche in recent years.
I pick Saw,The Crying Game,Planet of the Apes and Fight Club as having the best best twists I have personally seen,but then I have never seen The Vanishing and The Others.
Psycho's twist would have been great in the 60's but I knew exactly what was coming by the time I watched it.
Carnival of Souls surprised me (but I was 10 when I first saw it), probably was quite effective at the time,also.
I predicted the one in the Sixth Sense very early.I don't understand why so many people were surprised by that,it was very old hat trick,utilized in many American horror movies of the late 70's.Excellent movie nevertheless.
Although memorable and a very well made movie,the problem with The Usual Suspects is that the twist negates nearly the entire movie.The same can be said for Jacob's Ladder.Maybe a little too clever,depenRAB on the viewer I suppose.
After it seems she is the heroine of the movie,Tina being killed off in A Nightmare on Elm Street was a nice little twist that Wes Craven made on the slasher movie 'rules' established over the preceding 5 years.It worked so well that he did it again 12 years later with Scream,this time to more effect.