Brining another old thread back from the dead, probably should stay dead but I am bored...
Like others have said it is difficult to compare powers across stories, but we can try. The Valar struggled to shape the world and heal any hurts caused by Melkor. They are fast, but could not outrun Ungoliant which was a giant spider. We saw a fight between a Elven lord and Melkor, the elven lord was able to wound Melkor several times before he eventually lost. We have other examples where elven lords were not significantly more powerful then exceptional humans.
My knowledge of Comics is not the best, and characters power seems to jump all over the place but I would place a Elf Lord at a similar level to the Dark Knight movie batman. Sauron is a stronger level again but still vulnerable, I do not know maybe something like a typical Hulk.. bad example I think.
So I do not think Sauron could defeat Superman when he was written at his most powerful, and would still probably lose even against the weaker Supermans. So I would place Sauron similar in physical fighting ability as Golden Age Superman...
A valar would lose to Silver/Bronze Age superman, but probably comparable in power to Modern era (John Byrne) superman.
So
Elven lord = Dark Knight Movie Batman.
Sauron = Golden Age Superman.
Valar = Modern era (John Byrne) superman