Judging from all the comments and statements I've seen and heard lately regarding the prosecution of terrorists, it seems that many people are under the mistaken assumption that the U.S. Constitution (i.e. U.S. government) gives rights only to American citizens, and that we are "giving" terrorists the rights of an American citizen. These ideas are incorrect in several ways.
First, our founding fathers believed in the centuries-old philosophy of "natural rights," which states that all human beings have the basic rights to life, liberty, property, etc. The rights are yours simply by virtue of your existence as a human, and are granted by your creator, not by the U.S. (or any other) government or Constitution. The founders wrote the Constitution and Bill of Rights to recognize and guarantee those rights by prohibiting the government from violating them.
This leads us to the next idea: these rights do not belong only to U.S. citizens. As "natural rights" they belong to all humans, even though many governments do not recognize them in writing as ours does.
And lastly, the Constitution of the U.S. does not state anywhere that the rights only belong to its citizens. So, terror suspects retain the same rights as anyone else, whether or not we think they deserve them. It is not up to our president, a judge, a military officer, public opinion, or anyone else to deny them without due process.
As far as the debate over whether terror suspects should be tried in criminal court or military tribunal, this is not simply a decision of preference. There are certain criteria for military tribunal. In the case of the "underwear bomber," the suspect was not a uniformed member of any foreign military; he did not attack uniformed members of the U.S. military; the attack did not take place in a military combat area, or on military soil. And let's not forget that we are not technically "at war." Sending troops into combat and continuing to fund that combat does not make it so; neither does the president coining a phrase like "war on terror." Only Congress can make an official declaration of war, and that has not happened since WW II. It is an inconvenient yet constitutionally binding technicality that has been overlooked by every administration for the last 50 years.
Do I think that acts of terrorism are among the most hateful and despicable crimes ever devised by humans? Absolutely! Do I feel that convicted terrorists should get the full punishment allowed by law, up to and including the death penalty? Without question! But we cannot put suspects before a military tribunal just because government prosecutors feel criminal court is too problematic (inconvenient), or investigators would rather use "extreme" interrogation techniques than give Miranda warnings. Public outrage of terrorism is certainly justified, but it does not meet the criteria for military tribunal.
Rights must be preserved for all, or they can be preserved for none. The same precept applies to our right to practice any religion (or no religion) that we choose, even if it is not what the majority chooses; our right to speak our minds freely, even if what we say is unpopular (with the people or with the government); and of course all rights with which we are endowed by our creator. If we selectively deny rights to anyone, for any reason, yours could be the next to go.