1) He's retiring to Castel Gandolfo, which I believe is Italian for Gandalf's Castle :)
2)He's entrusted others with destroying an important ring
3) When he took on the role of Pope in 2005, he started wearing white
4) Has a cool staff
5) Gandalf- the grey pilgrim. Pope Benedict- went as pilgrim to 25 countries.
6) Saruman=Hans Kung. Think about it.
7) Associates with the powerful as well as the lowly.
8) Blows your mind with his wisdom
9) Speaks languages most people have forgotten.
10) Stood up to the Balrog of relativism.