A friend of mine just bought a pair of HD 600s, and after listening to them yesterday, I'm hooked I don't have ~250 to invest right now, but I've found the 580s for 130-150, and do have that kinda dough. From what I've read they compare pretty well to the 600s. I understand the "need" for an external headphone amp, but that's something I'll worry about if a problem arises. Price vs. performance, can I do any better? I've heard only good things about these, and just want to make sure there isn't some hidden catch.