HE-500 sounds just fine to me, even unamped. It improves a lot with with better sources and amps, but scales down very well too - certainly much better than Sennheiser HD6** series or AKG K/Q7**. And, personally, I would rather have the best headphone(s) I can buy now, upgrading my sources later. Even HD650 sounds OK to me unamped and is still preferable to my ears in this configuration to almost any mid level headphone amped by decent amps and sources. Maybe it was different in the old days, but nowadays I think technology has progressed enough to allow even cheap portables (i.e Sansa Clip) to output decent sound and to drive even most high-end cans acceptably. Well, that is unless we are talking about the really hard to drive ones, like HE-6 or K1000, but there are very few of those.
Edited by Pianist - 3/15/13 at 7:34am