I can't see Daniel Day Lewis as Greyback at all, and come to think of it I can't see Christopher Eccleston either... I saw him as Dr Who; he looks too much like a dorkier version of Jason Isaacs to be Greyback.
I stand by John Noble.
A picture of him as Denethor.
Also, I don't think of him as a Peodophile. I have a theory as to why he picks on children, which is probably slightly more family friendly than the notion of Peodophilia.
If we were going to be that picky about the books then whenever Tonks and Remus have sex then that might as well be considered bestiality - and Harry would be the result of the same thing, which in some way would give credence to all those idiots that hate Harry Potter because of its so called devastating influence on children!
I think there comes a point where you just have to sit back and think of it as fantasy, which it is. And the idea of children or anyone being turned into Werewolves is fantasy. Peodophilia is real, and I'd like to keep the two separate.