The video I've seen of GTA4 is irritating to me, because they still use canned animations... I find canned animations are distractingly inhuman. "Uncanny", yes. Especially if they're "realistic".
Well, for those who want to know more about the uncanny valley, there's a series on youtube. Although it's not exactly in depth (it bears an uncanny-valley resemblance to an actual paper on the subject ;) ), it has some interesting ideas and it's from someone who is definitely an authority in the field.