…at the last minute:

http://www.cracked.com/article_20637_5-movies-that-cut-insane-twist-endings-at-last-second.html

Interesting list and I was familiar with several of the examples.

Of the ones presented, I was most drawn to the alternate ending of Die Hard With A Vengeance.  I know there are plenty of people who view that film as the only Die Hard film that stands up with the classic original..but I’m not one of them.  I have the “Special Edition” version on DVD, but haven’t looked at it and didn’t realize that among the bonuses was the alternative ending presented in the article above.  Now having seen it, I can agree with the reasoning for not using that ending.  It’s rather downbeat and confusing…the whole spinning the rocket launcher on a table thing was odd and didn’t exactly build up the suspense as I’m certain the director hoped.  Ah well!

One film not mentioned is the James Cameron directed The Abyss.  While I suppose one can’t view the theatrical or director’s cut ending as a “twist”, it was strange enough in either version to perhaps qualify.

Thing is, I feel both endings were terrible.  Then again, there are plenty of people who defend the film, so your mileage, as they say, may vary…