Everyone hears things differently. I agree with rawrster about the futility of a $30 amp, however, I think my w3's sound worlds better with my Pd xm4, than just ipod alone. If you have a better source than ipod, then maybe you won't do better with an amp.This is all imho of course.
I prefer my W3s (and SE535s and RE0s and NE-8s) out of my FiiO E5 than straight out of my iPod or iPhone. But yes, my D10 does sound that much better.