Why do so many people want to see "The Dark Knight?"?

Hi all! I've always been a Batman fan as long as I can remember. I haven't seen the new Batman movie yet, "The Dark Knight," but I hear it's pretty good. Why do so many people want to see "The Dark Knight?" Is it because of Health Ledger's death or because many people are simply Batman fans like I am? Also, what was so special about Health Ledger anyway? He was just another person who happened to be an actor. He was from Austria so he wasn't even a real American anyway. hahaha! Many people die and get killed everyday, especially in the military. So, why do people worry more about celebrities' deaths than the dead military people who keep us free in this country everyday. Nothing in life makes sense to me. I just don't understand why some people tend to get more attention than other people. If only military people knew that many Americans really don't care about them in the first place, they would probably decide to come home ASAP. Any answers would be greatly appreciated! Thanks!