Hmmmmm. . .
The more I think about this case and the varying testimonies and Zimmerman's statement, I keep coming up with a theory.
We have Zimmerman, who is paranoid, packs a gun, and sees thugs and burglars around every corner.
We have Treyvon, who isn't a straight A honor student and has made a few boneheaded, typical teenager trying to be tough moves, but hasn't ruined his life yet, and may well grow up to be an okay person. (Like many of us who did a few boneheaded things in our youths!)
Treyvon is sauntering around the neighborhood with his skittles and iced tea. Who knows, he might have even been casing the place. Zimmerman sees him, goes into full on paranoid Dirty Harry mode.
At some point, Zimmerman confronts Treyvon. Treyvon is not an adult, he's a kid. Kids that age, by definition, don't have all their wiring, especially the planning and threat assessment wiring, in place. So Treyvon panics. He IS a kid, after all, and it's possible he was planning out something illegal, which makes HIM more scared (after getting suspended 10 days, if he did anything else wrong, his life probably wouldn't be worth living), and he feels really threatened, like this crazy guy might kill him. He's terrified, absolutely terrified. So he defends himself, probably more than he needs to, but that's kids in general, because he thinks if he doesn't he'll be killed, or something REALLY BAD will happen.
Zimmerman had all these fantasies built up about how he'd be the big hero and subdue the bad guys, but now he's got this strong young man attacking him BACK and Zimmerman's now scared. The kid is going for broke.
Zimmerman realizes he's out of his depth, he's scared now. He pulls his gun and shoots Treyvon.
The police come, find out the kid isn't squeaky clean, people heard a scuffle and saw a scuffle. Zimmerman's a property owner, an older guy. The kid's a teenager with a history. They decide to take the easy road.
And so a kid is dead because of a paranoid blank blank blank.

What a world.
That's my theory, anyway.