Just on a whim, I picked up the director's cut of Aliens.  I'm not a film person by any stretch so I am not sure if it is ok to say this or not, but in general, I like James Cameron's work.  Anyway, I figure seeing a few extra scenes or whatever would be fun while I watched one of those "great films" from when I was younger.  Lo and behold, the Director's cut weighed in at 2 hours and 39 minutes.  This was not just a few extra scenes thrown in, it was almost like watching an entirely different movie. Not that extreme maybe, but it made the film even better.  You learn more about Ripley, the colony, and some of the things that just seemed disjointed in the theatrical release fall into place (a la why Ripley seemed to become attached to Newt in a split second --- the background on Ripley is now there to explain that).  All in all, I'm really glad I picked it up!