I know, let's nuke Mecca and get it overwith!
Seriously, with almost 2 thousand U.S. dead and over ten thousand injured (and these aren't little shrapnel wounds, were talking missing limbs) there is no way you can do the math and say this was more cost effective then the occaisional bombing of a mobile radar station. The military itself says many units are close to being broken. Equipment is getting worn out, soldiers are serving extended and multiple tours. And we don't see the hidden costs of divorce, broken families, etc.
Colin Powell said , "You break it, you own it" when the invasion was being debated. No matter where you are on this debate, now we've got to try our hardest to make it work. If we do end up with democracies in Iraq and Afganistan, just imagine how awesome that would be! It will have come at a terrible price, though.
On topic, I work for a defense contractor, and after 9/11 a colonel in the Marines I had developed a friendship with via work told me that if they went to the draft, they would start with 21 year olds, go up to 28, I believe, and then go younger. I think he said they wouldn't want me, even if I volunteered, after age 30. I was 27 at the time, and I greeted that with mixed feelings, since I had toyed with joining up, especially after the attack (had I been single, I probably would have done it).