I still don't think Anakin physically dies. Just the humanity of Anakin dies. If Anakin had died completely and Vader was just a collection of pieces brought to life, then he would show no compassion for Luke at the end of ROTJ and wouldn't have saved him. Also, spoilers have said that after the operation, Vader asks what happened to Padme and the child(ren). If this was a completely new being, he wouldn't have asked this and then shown sorrow and regret through "anguished screams." Anakin=Vader I tend to agree with this theory.