I think the most interesting aspect of this film is that unlike classical Hollywood films it offers no objective narration and has a completely fixed point of view.
As Travis appears in almost every shot, we are only able to see events from his (very disturbing) perspective. There's also an unusual number of point-of-view shots. Scorcese uses the technique of slow motion, usually reserved for romantic scenes, to depict the heightened senses of the character as he views prostitutes and pimps on the side of the road.
This film is fantastic in many ways, but I never really grasped the ending. The transformation of Travis from an outcast to a societal hero seems almost in the realm of fantasy, which doesn't work well when the film otherwise tries so hard for realism.
It occured to me that perhaps the ending is a fantasy. This is possible considering the ambiguity of the last sequence. Maybe the portion of the film after the gunshot is just the inward thoughts of Travis as he dies. It makes more sense to me at least... Any thoughts?