[Hot, crispy nice hobbit]

Yes, this was Sauron in his prime (well, not with thousand s of orcs, but in his own power terms definately).

(Kudos to Eönwë)

Gee, Sauron in his prime almost meet his match upteenth times, never with a Valar:

1. Felagund (Finarfin's son)

"Then befell the contest of Sauron and Felagund which is renowned. For Felagund strove with Sauron in songs of power, and the power of the King was very great; but Sauron had the mastery, as is told in the Lay of Leithian"- Of Beren and Luthien, The Silmarillion.

2. A cloak

"Then Sauron spring upon Luthien; and she swooned before the menace of the fell spirit in his eyes and the foul vapour of his breathe (Yuck). But even as he came, falling she cast a fold of her dark cloak before his eyes; and he stumbled, for a fleeting drowsiness came upon him."- Of Beren and Luthien, The Silmarillion.

He was owned, of course, by a Maia:

"But no wizardry nor spell, neither fang nor venom, nor devil's art nor beast-strength, could overthrow Huan of Valinor; and he took his foe by the throat and pinned him down. Then Sauron shifted shape, from wolf to serpent, and from monster to his own accustomed form; but he could not elude the grip of Huan without forsaking his body utterly."- Of Beren and Luthien, The Silmarillion.

I can't visualise that Sauron would ever gain enough strength to release Ol' Morgy, if he can't even take on a half-Maia's garment... But that aside, having rested enough from jet-lag after his holiday at Numenor, Sauron got owned by a motley crew:

'I was the herald of Gil-galad and marched with his host. I was at the Battle of Dagorlad before the Black Gate of Mordor, where we had the mastery: for the Spear of Gil-galad and the Sword of Elendil, Aiglos and Narsil, none could withstand. I beheld the last combat on the slopes of Orodruin, where Gilgalad died, and Elendil fell, and Narsil broke beneath him; but Sauron himself was overthrown, and Isildur cut the Ring from his hand with the hilt-shard of his father's sword, and took it for his own.'- The Council of Elrond, LOTR: The Fellowship of the Ring.

I figured that Sauron only wanted a little sandbox of his own in Middle-Earth without any trouble from Manwe. He pro'ly shook his fists and yelled threats about letting Big Brother out if the big kids won't let him alone... Trouble is... They took his threat seriously...

"I'm TELLING!!!" - Sauron, rising in spirit form from the waves drowning Numenor.