Yikes! It's been awhile since I've been here. Is it too late to say Happy 2010?!
My last post talked about the wants of a character and if they're important to the character, they will be important to the reader/viewer, meaning that said reader/viewer will stay invested in your story - that's the theory at least.
Building on top of that, the climax of your story should be violent! If achieving the goal is a matter of life or death to your character (not necessarily in the physical sense), the climax of this quest, the moment where the protagonist and antagonist go head-to-head... well, if it's not violent, it's a bit of a letdown, wouldn't you say? If a goal or want is a matter of life or death, it stands to think that a character will do everything in their power to achieve it. It also stands that there's an antagonist out there also willing to do anything to stop our hero. A perfect recipe for a violent confrontation of some sort.
Again, this idea of the climax being violent doesn't have to apply strictly to the physical The climax can be emotionally or psychologically violent too. Obviously, film and screenwriting lend themselves easier to a physically violent climax, but ideally, if you can combine the three, you're onto something special. An example off the top of where you have a trio of climactic violence is in Fight Club between Tyler Durden and Jack:
A most excellent climax if ever one existed.
Coming Soon: How you can learn everything you need to know about storytelling from boxing and MMA.