Sorry, I'm not going to vote in your poll, since I think the choices you gave aren't worth answering with, but I will give you my opinion.
As one of those that have served in uniform, back in the old days when judges with juvenile delinquents would oftentimes give the choice of "3 years military or 3 years jail", I can tell you beyond a shadow of a doubt that there are people that are not now, nor will ever be, suitable for military service. Contrary to those that believe that people that join the military aren't very intelligent (okay, there are some lunkheads, but I was operating nuclear power plants in the navy, and believe me when I tell you that they don't hire dummies to do that job!!), or are "war-mongers", "haters" or whatever other petty little label they want to use for people in the military, there are certain qualities that make a person a better soldier, sailor, marine or airman than others would be.
Mostly, it's not just a love of country (usually quite strong in those that serve), but the belief that they can make a difference, and the longing to do so. Back in the Carter and early Reagan eras of the military, the volunteer military almost ceased to exist, and you had people that came in primarily for educational benefits and careers. Nowadays it's not much different, but you are seeing a higher percentage of people who are doing this for their love of country, rather than the 100% tuition coverage (although they do take advantage of it......one air force tech sergeant [e-6] that I work with has his bachelor's degree, almost has his master's, and will likely earn his doctorate soon after he retires).
But to ask military service of every person would be to make the military worse than it's ever been. Okay, in times of great need (like a world war), you might need to institute the draft, but I don't see the need for that at this time. Even with the media giving daily reports on all the negative aspects of Iraq, you still have people willing to go into the military. Certainly not in the numbers prior to the Iraq invasion, but nevertheless in numbers higher than I expected with all the bad press the situation in Iraq gets on a daily basis. However, the single biggest thing that you're taught in basic training is how to rely on your buddies, and make certain that they can rely on you. Teamwork, in other words. And there's just some people in this country that couldn't manage that to save their lives, and likely would cost us lives if they were to serve in battle.
So to answer the question should there be mandatory military service, my answer is NO. The cost would be too high, in lives moreso than money.