I would think the "aha" moment is the moment the main character becomes an "internal hero". Once the internal metamorphosis has occurred, it can manifest externally in the final showdown, where the hero is finally triumphant.

Scott,

What do you think the "all is lost" moment is in Star Wars? I've heard people say it should absolutely, definitely take place around page 75 in a script, yet I'm not sure that happens in Star Wars. The "all is lost" moment seems nebulous at best.

@Joe: I've read some analyses which put the spotlight on the trash compactor as an All Is Lost type moment, but while significant - and certainly symbolic (descending into hell / rising from the dead / baptism) - I don't think it has the emotional weight of a later event: Obi-Wan being killed by Darth Vader. Yes, Luke, Leia, and Han manage to escape, but it's a real blow to Luke to lose his Mentor. That sets the stage for Act Three -- preparing for and attacking the Death Star.

So with the caveat that all of these categories are in some way 'false' because story is organic and all that, the way I look at it is the big All Is Lost moment is Ben's death. Now the undermanned and seriously underdog rebel forces have an almost impossible task -- to drop a bomb down this tiny opening in the Death Star, and all without the support of Luke's Mentor.

I'm with Scott. Def think it's the death of Obi Wan.

They even have a little mourning scene, until Han and some Tie Fighters literally interrupt it.

A lot of Lucas's early work does a good job of keeping the adventure moving while cramming in character. That's probably the nature of the genre as well.