mm the problem with threads like this is that if there is a film you haven't seen, you end up watching it knowing that there is a twist, which in turn devalues the twist.
anyway, in no particular order:
- the crying game; the movie i found tedious, the twist was...
- fight club
- deja vu (wasn't really a plot twist so much as a realisation that there was a fairly deep subplot).
- wild things
I hate the 1st Saw because of its ending. People think its brilliant because you were totally surprised when you found out who the killer was. Except that its someone with no relevance to the plot whatsoever. The film tries to trick you into thinking its one of the main characters but in fact, its just someone we saw for literally 1 second.