The Greatest powers on Middle Earth (3rd age)... Listed in order

[Manardariel]

I´d say Galadriel is more powerfull then Elrond, and Smaug shouldn´t be in there at all. My list is:

1. Sauron
2. Gandalf
3. Saruman
4. Galadriel
5. Elrond
6. Balrog
7. Nazgul
8. Hobbits (as a unit)
9. Treebeard
10.Aragorn
11.Tom Bombadil
12. Cirdan
13. Arwen

Explanations:
Galadriel is more powerfull than Elrond, because she controls more land, has a greater impact on people , is older AND ever considered taking the ring. This means she seriously wants power, wants to rule. Elrond never showed this intrest in power. He´s wise, but he´s also rather passive.

Smaug isn´t in there, because for one thing he´s dead, for the other his presence never threatend the whole of ME. The dwarves and Dalemen were the only ones scared of him.

Hobbits:
This will need some explanation. All hobbits are powerfull, but only if they act together. Frodo cold only destroy the ring because Sam helped him, and Merry could only destroy the WhitchKing, because he followed Frodo out of the Shire in the first place. Besides, their home, the Shire, is one of the places where there is still power. Gandalf says so in FotR:

There is power, too, in the Shire, but of another kind.

Hobbits are a definite power in ME. A hobbit destoyed the ring. A hobbit slew the Witchking. They have power.

Arwen:
Arwen is on there because her love is one of the things that makes Aragorn go on, that protects him. Elrond says they can only marry if Aragorn is king. That probabyly was one of Aragorn´s chief motivatoins. Also, Galadriel (Aragorn´s Grandmother-in-law) gave him the Elessar, that would later be his symbol as a king. Arwen made the banner of Elendil for him, and Arwen protected him. She isn´t physically powerfull, but her love and presence make Aragorn even more powerfull.