Rev 17:3 is clearly explained in verse 7-11. This is not literal Babylon, its the "Mystery" Babylon.
Rev 17:7-9
7 And the angel said unto me, Wherefore didst thou marvel? I will tell thee the mystery of the woman, and of the beast that carrieth her, which hath the seven heads and ten horns.
8 The beast that thou sawest was, and is not; and shall ascend out of the bottomless pit, and go into perdition: and they that dwell on the earth shall wonder, whose names were not written in the book of life from the foundation of the world, when they behold the beast that was, and is not, and yet is.
9 And here is the mind which hath wisdom. The seven heads are seven mountains, on which the woman sitteth.
(KJV)
This hardly sounds like its speaking of America to me. Seven mountains? Sounds more like Rome to me. Acient Babylon as we all know was a city In Iraq. But mystery Babylon is seven mountains that the women or whore sits on in Revelation. IMO these are two different Babylons and neither appear to be America.
As for Daniel 7. It also is explained a few verses later.
Dan 7:16-24
16 I came near unto one of them that stood by, and asked him the truth of all this. So he told me, and made me know the interpretation of the things.
17 These great beasts, which are four, are four kings, which shall arise out of the earth.
18 But the saints of the most High shall take the kingdom, and possess the kingdom for ever, even for ever and ever.
19 Then I would know the truth of the fourth beast, which was diverse from all the others, exceeding dreadful, whose teeth were of iron, and his nails of brass; which devoured, brake in pieces, and stamped the residue with his feet;
20 And of the ten horns that were in his head, and of the other which came up, and before whom three fell; even of that horn that had eyes, and a mouth that spake very great things, whose look was more stout than his fellows.
21 I beheld, and the same horn made war with the saints, and prevailed against them;
22 Until the Ancient of days came, and judgment was given to the saints of the most High; and the time came that the saints possessed the kingdom.
23 Thus he said, The fourth beast shall be the fourth kingdom upon earth, which shall be diverse from all kingdoms, and shall devour the whole earth, and shall tread it down, and break it in pieces.
24 And the ten horns out of this kingdom are ten kings that shall arise: and another shall rise after them; and he shall be diverse from the first, and he shall subdue three kings.
(KJV)
The first kingdom was Babylon which became world empire in 606 BC. when it conquered Egypt. Nebuchadnezzar took over the empire from his father and made it a world kingdom. Second kingdom was Media-Persian Empire. The Babylonian empire was conquered by the Medes and the Persians about 530 BC. A few hundred years later, the Greeks became the third empire, when Alexander the Great conquered the Persians. Rome became the greatest Empire around 68 BC. Note this kingdom was not given a name of an animal, but was described as dreadful terrible and exeedingly strong (Dan 7:7). This kingdom gained world power then disapeard. (note: this information was taken from Hal Lindsey's Planet Earth 2000AD.)
I believe this Empire will be revived just before the return of Jesus Christ as described in Revelation 17:8 ;behold the beast that was, and is not, and yet is. I do agree that American will have to somehow be diminished for a Revived Roman Empire to happen, but thats not really hard to imagine the way things are going in America today.
Here's a few actual news links that point in this direction
Survey shows EU Citizens favour globalisation - http://europa.eu.int/rapid/start/cgi/guesten.ksh?p_action.gettxt=gt&doc=IP/03/1553|0|RAPID&lg=EN
This ones a bit old, but interesting non-the-less.
Chicago Tribune, 6 January 2002
EU in position to be world’s next superpower - http://www.worldpolicy.org/globalrights/europe/2002-0106-Chicago%20Tribune-European%20superpower.html
An Emerging EU Superpower & the U.S Cold-War Clash
http://www.scoop.co.nz/mason/stories/HL0306/S00144.htm
Just a few, but enough to make the point. I expect the EU will soon drop its extra members down to 10 as predicted by Daniel and force America under her control through economics. Either that, or America will either fall, or be destroyed.