Vash left them laying there on the ground after he defeats Knives.

Its not that hard to figure it all out. The show has very little plot....

Vash doesn't even want to kill anyone.
Knives is like Sephiroth and has a massive breakdown as a kid because he finds out he is different from everyone else, except Vash. He then wants to destroy everyone.

Good vs. Evil. Brother vs. Brother. One who wants to kill everything vs. his brother who doesn't want to kill anything.

The brother who doesn't want to kill anything stops his brother without killing him, thereby saving his idiology of not killing someone (although Knives alrady made him do it earlier).

Don't get messed up in the Anime symbolism. Its quite a simple story...

That's seems to overly simplify the story.

Yess. We weren't (at least I wasn't) argueing about the story. I just missed a few detials, (don't know how, but when I watched it agian I saw them) or just was wondering way a certain character did/n't do certain things. 'Cause I question everything, as long as it dosen't matter.

I always wonder "what if Vash killed?" Would the show be as good, or is it his conflict that makes it good?

It would have lost alot of its meaning. Most of the plot is driven by the fact that he dosen't kill, so unless they found something to replace that it would suck. It would just be him showing up in a city, killing the guy with one shot, and thats an episode.

i realy did not care for vash i thought he was a wuss the only real reason i watched was becuse of wolfwood. he rocked and i think his deathspoiler was both very cool but also making me pissed off at the same time because he dies, he kicksspoiler.
knives was bad asss. there is nothing else to say.
but vash i had found that was to cocky in every episode he makes it seem that nothing could kill him he is in lack of a better word invincible, and that makes the show realy bad but thats my two doller bill give it back!
better words
invulnerable, unbeatable, unconquerable, undefeatable, untouchable. ok maybe not that last one.

You know, there's a reason people mark spoilers.