Zimmerman tried to play hero and it blew up in his face. If he was that worried about his community, either leave it to the cops or move. Take care of YOUR property, and leave it at that.
I can't comment as to Trayvon's actions (it sounds like he acted like a punk though...worthy of an ass kicking, not dying) on account of him being dead and not having his side of the story.
But because guilt cannot be proven, (beyond reasonable doubt and all that), Zimmerman MUST go free. It sucks, but its the way things work, better 100 guilty men go free than 1 innocent man, etc, etc, etc. It should not be easy for someone to be thrown in jail for the rest of their life/be put to death. I do feel bad for the prosecutor because they don't have a whole lot to work with. Their "star" witness did more harm than good.
I think prior to some of these testimony's manslaughter was a real possibility, but at this point the jury is probably so screwed up on how they feel about this, who knows if they will find him guilty.
I also think saying Zimmerman's eagerness to investigate was racially motivated may be a stretch, but even if it was, so what. I can sit on my porch and yell at the black kids going to school till I lose my voice, I can call the cops on every mexican that cuts through my alleyway, I can make holocaust jokes at every jew I see. Being a shithead isn't illegal.
People are generally shitty, and as it stands adding "race" to a crime adds what, ten extra years? Still have to prove it was done.