[Iarhen]

I think I would modify your list. Sauron would be top of all, followed by Gandalf the White… but Elrond and Galadriel are clearly misplaced as well as the Witch King and Shelob. I would re arrange it like this:

1. Sauron
2. Gandalf the White.
3. Saruman (before Gandalf defeated him)
4. Balrog.
5. Galadriel.
6. Elrond.
7. Fangorn.
8. Witch King of Angmar.
9. Aragorn.
10. Shelob.

I would have to say, though, that it would depend on the circumstances surrounding a confrontation between the characters. For example, if Fangorn entered Shelob’s lair, he would, most probably, be eaten. And if Shelob did the same, she would be crushed. The Witch King was afraid to enter Lorien because of Galadriel, but I have my doubts of the outcome if the Witch King confronted personally the Lady (especially with the sword… but she must have some kept tricks under her big sleeves!). And Saruman was terribly powerful, but after his staff was broken, he would prove no match for the Balrog, Elrond or Galadriel (the ones immune to his voice).