You didn't read all the responses did you?
I reckon a better ultimate move for naruto would be for him would be something like dance of a thousand blades, where he would release wind blades all around him, kinda like neji's kaiten, only it cuts the opponents instead of pushing them away. I guess it would look like a huge rasengen, only with naruto in the middle of it all, and without him having to contain it, i.e. rassngen without before naruto completed the third and final stage.
the best i guess is a harem no jutsu + kage bunshin.. that would be freakin' awesome.
No more ramen for naruto.. That's bad news..
What if his ultimate move was "injecting" the poisonous kyuubi chakra into an opponent, and then uses a rasengan or something to make the person blow up? He would need to control the kyuubi chakra, which he can do with sage chakra.
72 hours of hell!