Personally i listen to a lot of metal, death, heavy, power and so on... I actually would recommend something more neutral, slightly warm signature works also. I personally have not heard that many headphones and i can only give recommendations based on reviews mostly.
I have KRK KNS 8400 as my portable headphones, very detailed and slightly bright sound signature, works great for most metal but something like older Blind Guardian can sound a bit anemic mostly because it is bass light to begin with. Something like Sonata Arctica sound very nice with the 8400. But i think most would find them to be a bit too bright, personally i have no issues with them at all.
I will list some headphones i think could work in terms of sound signature / sound quality. Nad Viso HP50, Shure SRH 840, KRK KNS 8400, Akg K550 / 551 and maybe the K545, SoundMagic HP100. Those are pretty much over ear models and some of them are fairly large for portable use. But they are all sealed and can work as portable. Cant really recommend any IEM's.
Edited by Notus - 7/3/14 at 3:18pm