Kamui Shiro...a 16 year old boy with a very important destiny, and one of the very few able to choose his own future...
Born of Toru Magami, who knew her son would be very important, he has the fate of mankind in his delicate hands.
His name, Kamui, has two meanings: "He who hunts the authority of God", or "He who hunts the power of God", and his surname could also be taken two ways - Shiro could mean he is of the forces of light, the Ten no Ryu, sworn to protect the Earth; or that he is destined to choose to be one of the beautifully white-winged, yet destructive Chi no Ryu, those who aim to destroy mankind for the Earth's sake.

Anime:
In the anime, Kamui seems to be protrayed as a rather weak-willed young man, who would rather let events happen to him rather than shape them for himself. He doesn't appear to have any comprehension of the task ahead of him, seems to only cry when two people die and ignores the fates of the others, and has a disconcerting liability to sit around looking pretty and doing nothing. It's hard to really care about someone like that, ne?

Manga:
Of course, things are different in the manga, or it would be unlikely X/1999 would have become the hit it is in the shoujo manga world. This Kamui isn't the kind to let events and people happen to him. He knows what is happening, and at least has enough backbone to deal with those that would harm him. From the very beginning, we see him battling Curse-Zombies, and threatening a raven that was watching him. Also, he appears at the beginning to have very feelings of care towards others. He warns Kotori off from him and even though can see her sadness keeps a blank expression on (however, when she collapsed, he did take her to the school hospital), and when both she and Fuma approach him he ignores them.

X Japan song:
'Crucify My Love' is the one that springs first to mind, but I'm sure I can think of many others.