The death of Trayvon Martin sounds very much like a murder. If Zimmeran followed Martin and confronted him in any way, then Zimmerman provoked a confrontation and he can't hide behind a "stand your ground" law. A hoodie and being african american isn't probable cause for anything. It will be murder and quite possibly a hate crime.
The case now has the proper attention it deserves. It will get the investigation it deserves. If it turns out that the details we have heard turn out to be true, then some real house cleaning needs to take place, not just in Sandford but needs a discussion about the neglect of justice on a broader scale. The belief in equality and fairness has been in retreat for some time, and the Martin case may well be a brick in that wall.
We all probably know people that have concealed gun permits (well at least I do, and I live in NC). Other people I know have a gun ready at their house. Most of these people live in the country where, if you were to call the authorities, they would not arrive for a long time. I fully understand that and, if I lived there, I would do the same thing. Those people don't advertise it.
If you live in the area I do, the dangerous areas are pretty clear and most people are very secure. Extreme crimes do occurr (Google Eve Carson), but not in public areas we circulate in. Still, I know a guy that carries a gun. This guy makes a point of telling people about it and makes a point of regularly broadcasting how no one better mess with him. I avoid this guy for a couple of reasons: blow-hards are really boring and annoying, and he represents an unnecessary danger. A constant sabre rattling of what he is going to do if anyone gives him trouble is the kind of thing males typically do in High School. It is testosterone fueled teenage bravado - which can be dangerous in High School - but give that same arrested personality a handgun and they immediately become a potentially source of an immediate and painful death. Yes, the risk is remote, but so are many other risks that I don't engage because I have no reason to engage in. Yes, some of the guys attracted to guns and probably the last people you'd like to have carrry a gun.
Guns have their place for personal defense, but guns are extremely potent weapons that can kill by-standers (I've never gotten a stray punch from a fist-fight except when I stepped in to break on up). For that reason, crimes involving guns need to be tried aggressively and "stand your ground" defenses need to be treated with a critical light.
The biggest issue is going to be the role of race in the Trayvon Martin case, but a gun likely moved the crime from an assaul to murder.