Frankly I think Zimmerman's own testimony carries more weight than most here are prepared to admit.
Keep in mind that the police arrived VERY rapidly after the shooting, and this man had not ever shot anyone before, certainly not killed anyone before, he was probably very much in shock about what just happened, still dazed from being beaten, etc.
He did not have a lot of time or the right mental state, and certainly not the benefit of 266 pages of forum posts analyzing everything, or a month of stewing on details, to figure out which little wrinkles which, if he added to his account of events, would set him up in a better position to avoid charges.
Sure, general rules like "it's always a good idea to claim self-defense" would possibly have occurred to him even in that state, those are obvious, I'll grant that. But again, this is not a man who appears to have planned this in any way, not an evil Bond villain mastermind.
This is a man who was just surprised by being attacked, and surprised by having to kill someone. He didn't say anything which didn't fit with what John the *eye*witness said. He didn't say anything which aroused police suspicions much if at all, he didn't say anything inconsistent with the evidence at hand. So I tend to think his testimony is one of our best resources. I look forward to when we have more of it.
And to those saying he might be found recklessly negligent and held accountable on that basis, if each individual piece of the puzzle (legal to carry the weapon, legal to question a stranger in his community, legal to act in self defense) is kosher on it's own, how can they really become criminal when combined?