The Powers of the Istari

[Daniel Telcontar]

I agree with Burrahobbit, the reason Gandalf did not look into the palantir was of fear of revealing himself, not because he feared to lose a contest of will.
I am unsure if Sauron is stronger than Gandalf or if it is the opposite. Sauron was Melkor's mightiest servant, and learned much sorcery from him. When he attacked Minas Tirith (in the sil, not the capital of Gondor), it says that he came against them himself, meaning he is quite powerful in combat. On the other hand, when Gandalf first enters Dol Guldur, Sauron flees before him. I think however, that he did not flee because he feared to lose a fight, but to be exposed as Sauron himself.
I think Sauron was stronger than Gandalf when it came down to sheer power, but it is probably not much.