[Aratlithiel]

I don't agree that Saruman is under-developed...of course this opinion comes from also having read Unfinished Tales and learning of Saruman's jealousy of Gandalf at the council of the Valar. That small chapter ( The Istari) told me everything I needed to know about Saruman's character and allowed me to fully appreciate the motivations behind his actions in LotR.

Saruman is one of those guys who achieves a certain level of respect and has the opportunity to do great good with his powers and knowledge (for which he would be 'canonized' for lack of a better word) but always has that seed of insecurity in him which gnaws at him and drives him to desire to prove himself the wisest, most powerful and most worthy of praise. It was this desire that led to his undoing and Gandalf's lack of it that led to him taking Saruman's place after his fall to evil. So instead of 'canonization' Saruman dies in the dirt and is reviled in history.

Saruman knows all too well that Varda places Gandalf above him. I believe the turning point for Saruman was when he came to realize that Cirdan had entrusted his ring of power to Gandalf and not to him. To him this must have been insult added to the injury already inflicted by Varda. Everything Saruman does after that seems be an effort to prove to Varda that he was the better choice and to gain confidence in himself that he is indeed "better" than Gandalf. He has always had a sneaking suspicion that's he's inferior to Gandalf (although I don't think his pride would allow him to admit that to himself outright) and I believe his choices are an effort to prove to himself that he is in fact superior.

I see Saruman as akin to Iago in Othello. Really, everything he does is in an effort to bring down one he knows is superior to him simply so that he can stop feeling inferior.