in episodes 133 - 135 of the anime of course sasuke won naruto had almost no skill during that part of the series so ofcousre sasuke won. But in damage i would say rasengan all the way. And if you read the manga then you see the rasen shurikan and the giant rasengan.
if you saw the ep where kakashi stoped naruto and sasuke from fighting on the hospital roof then you have to say rasengan. i mean look at it chidori has more power at the start but it then closes its power really fast rasengan not much at start but its follow up is much much stronger then the chidori. and yes i am a naruto nerd
Rasen Shuriken for sure, it is probably the most devastating attack in Naruto's arsenal, and, if you combine that with his Sage form, he is basically at the 4th Hokage's power, probably even stronger.
I haven't watched Naruto since Sasuke went bad, and I bet I didn't miss much because I heard it was nothing but filler episodes after that.
Anyway, I would get rid of both moves. Ulitmate attacks just ruin any show. It is ridiculous when a character is getting their butt whooped and then they just pull that move and win, I mean, why even waste time fighting when you are just going to do that move.
Eh, Naruto after Sasukes whole "I am gonna kill my brother, so screw the leaf village" thing just went down hill till Shippuden came out, and now its a lot better.