Melkor the Valar from the Silmarillion. The original dark lord and Sauron's master.
http://www.glyphweb.com/arda/default.asp?url=http://www.glyphweb.com/arda/m/melkor.html
http://en.wikipedia.org/wiki/Melkor
The wikipedia entry is accurate. Apart from it says that Melkor was the most powerful Vala. He was more powerful than the rest of them combined.
Eru WAS the one true God, but the Valar were described AS gods compared to anyone else in Arda. The Maiar were demi-gods. Everyone else was either Kelvar or Olvar.
Like the Egyptians, they didn't have ONE God, but a BUNCH of gods with some better than others. Like the Valar. Melkor was on top at first then sunk right down to #15 or #14 since he was discluded as a Valar later on.
I think he's somewhere lower than that by now. In any case you could very well describe them as godlike, I do agree with that. But they were also tangible and able to be wounded. Assuming (Key word there) Ragnos has uber powers on par with say, blackholes, pushing people into space, etc. it's conceivable that he could KO a Valar that way. It's not an instant death since they are immortal but for the sake of the battle it would be a KO.
Well, Gandalf the Grey was in fear of a Balrog (although he defeated it). Gandalf was probably the power of a good Jedi Master (like the same level as Yoda). This Melkor had an army of Balrogs and "god-like" power. Ragnos also had "god-like" power. This is actually close, methinks. I can't say who would win, this is what happens when you have 2 super beings fighting.