I haven't read many of the EU books, but I love Rogue Planet. It's set a few years after TPM, and Qui-Gon (er, hope I am not spoiling you) is actually speaking to both Anakin and Obi-Wan, but Obi-Wan *refuses to believe it*. And Anakin's all: heh, Qui-Gon just visited me in my dream. He says hi!
Obi-Wan: O.O SHUTUPNOW.

I think Anakin/Vader was delusional from sometime in RotS to RotJ, but never completely sold on the idea of being evil or whatever, so much as thinking he was trapped. And accepting it.