Gandalf vs. Sauron

[NightKnight]

It never says Olorin was the "chief maia". I don't think there was one. It's said, however, that he was the wisest.
Maybe he was equal to Sauron, maybe he wasn't. Since he was an Istari he had limitations. Imagine yourselves stuck in a wooden box. Would you be able to jump, run, swim etc.? I know this has been discussed somewhere. Unfortunately I don't know where, or how to do links.

[Boromir88]

Whether, Gandalf and Sauron are equal, not sure, if they aren't they are pretty darn close. Gandalf did fight with Sauron when Frodo had the ring on at Amon Hen. Really who is more powerful? Don't know, just Sauron, Gandalf, and Galadriel are probably the top three during the war of the ring.

[NightKnight]

I'd place Saruman over Galadriel, seeing as he actually is a maia. There is (was) a discussion on this in the N&N forum, on the 10 most powerful beings in ME.

[obloquy]

Let us all defer to a local authority on the matter: here and here and here and here and here and here. Yeah, that's a mess of stuff and sometimes it's more focused on Gandalf and Saruman rather than Sauron, but ehh...

[gorthaur_cruel]

In the Two Towers after Gandalf came back he said that he had become equal with the head nazgul.

He said that? The closests quotes I can think of is Aragorn saying, “The Dark Lord has Nine. But we have One, mightier than they: the White Rider. He has passed through the fire and the abyss, and they shall fear him.”. That suggests that Gandalf is stronger than all the Nazguls, which includes the Witch King. The other quote is when Gandalf replies "maybe", when Denethor says that the Witch King was a match for Gandalf.

I have questioned why is Gandulf not at least equal to Sauron since they are both Maia?

Not all humans are equally strong. Just because they're of the same race does not mean that they are equal. After all, the only difference between the Valar and the Maiar is power, since they were all Ainur to begin with. Gandalf's strengths lay in wisdom, rather than power.

Especially since Gandalf had a ruling ring and Sauron did not have his one ring.

The "Ruling Ring" refers to the One Ring. Gandalf had a "Ring of Power", not a ruling ring. However, Gandalf's Narya did not help whatsoever in battle, as is made clear. None of the Three gave any fighting advantages, but rather the power to preserve what is fair.

Also according to the Simillarion, Gandalf should be even better it says that Olorin was the chief Maia.

It says that he was the wisest. Do you think a...let's say, a wise old professor could kill a champion swordsman? I don't think so.

There's almost no doubt that Sauron was the more powerful in terms of strength between the two (despite the fact that Gandalf is my favorite character ). Tolkien wrote in one of his letters that if Gandalf decided to use the One Ring to fight Sauron 1v1, it would have been an even match. He also wrote that neither Galadriel or Elrond would've been able to fight Sauron 1v1 even if they used the One Ring.