What element is best fused with rasengan

yup

ur wrong sasuke is a lightning type and its water over fire, fire over wind, wind over lightning, lightning over earth, and earth over water.
http://leafninja.com/jutsu.php

rasengan is a wind type jutsu, so i think they can only add wind to it?

D; I really wanted the wind style: rasen shuriken... but it's impossible, since it damages naruto's arm D:
hmm i'll go with the will of fire! or maybe lightning.
yup yup, FIRE OR LIGHTNING.

what makes you think the others dont dmg the user as well... lets take fire? im assuming it blows up in your face, that wouldnt be pretty. water giant vortex of water crushes your arm from water pressure. earth i see sand, sand is annoying when it gets in your clothes, lightning, i think of chidori, only spininnng

me too

as though one element isn't enough? Lightning makes most sense but I think anything will seem a bit much.

yes yes i agree lightning would be good
yea lightning

FIRE ELEMENT!!!

No matter what element you add to it, it will still cause self-damage.
Because Naruto used the wind-element on it and it caused some damage to his arm
from the force of the wind.
So let's say you add fire elem. I think it will burn up your arm?
Or lightning will probably shock you once you attack the target.
And water....as Jmonkeylover said, you will get hurt from water pressure.
And as for earth...I wouldn't want rock to slap my face while I'm charging the Rasengan up.

with earth i can see either mud, sand or rocks... all three of them sound annoying to alkamos... so i vote against earth

annoying me*