In terms of portability I'd go for the ATH-M50, they're great cans, very flexible and pretty light. The 580 can only rotate each side only a small amount so you can't really put them on your shoulder. I wouldn't recommend the DT770 or Q40 as they can't rotate at all, plus they're both huge, so they'll squeeze your cheeks when you sit them on your shoulder. The M50 however, perfect for on the go.
Edited by Vicx - 7/26/12 at 8:23am