I actually like Disturbed, but to me from their second album on they're hard rock bordering on metal. Their first album is the closest thing they have to nu metal. When I think of nu metal I think of bands like Korn(which to me have their own sound), Static X, Mudvayne, etc and others I've forgotten or never got my attention. I've barely listened to Deftones either, but from what I heard of them I wouldn't even call them nu metal. I haven't listened to any core bands either so I can't really comment on them, but I'll guess there isn't much worth looking for, haha.