Just to respond to this, because no one else has:
One of the main differences between the Virginia Tech thing and our troops is that our troops volunteered to put themselves in harm's way, and they are compensated (not well enough in my opinion but if you're an inner city minority or a uneducated southern youth there aren't all that many good options... and they are the people who make up the majority of the military) for their time and efforts.
Generally speaking, men who are killed in a war are not considered murdered. Their deaths might be tragic, but by definition, men die in a war. We know it's going to happen. I hate to make it sound like their deaths are not "special" but... statistically, it has to happen to some people. Of course, then you hear that a lot of the casualties in Iraq and Afghanistan come from things like friendly fire, auto accidents and roadside bombs (i.e. the soldiers didn't come under fire by an enemy; they were just at the wrong place at the wrong time), and all you can really do is shake your head and wonder if there might be a better way.
At the same time, the Virginia Tech thing, to me, doesn't deserve the attention it's gotten. Some guy got pissed at the world and killed a bunch of people. The media can't stop talking about it, and they're discussing every detail of the event obsessively. Doesn't it occur to anyone that this coverage might encourage some other idiot with a similar psychosis and/or collection of firearms to go out and do the same thing?
I don't think flags need to fly at half-staff when a soldier is killed. I am sorry to say that, but in a time of war, dying is something we expect to happen to soldiers.
I also don't think flags need to fly at half-staff for a bunch of people who have been murdered. It's a tragedy, yes, but there certainly have been other news-worthy events where a couple dozen people have been killed that have *not* been worthy of a lowered flag. I suspect rather strongly that if a gunman killed 32 people in, say, Montana (as opposed to 20 minutes away from Washington DC, NYC or Los Angeles), it would've been a 5 minute story on CNN before they went back to talking about the latest abducted white girl story.