Greetings all, I'm a newbie in the world of stereophile in search of wise guidances. Recently been planning to upgrade my cans but can't decide between two choices: AKG K601 and Grado SR80I. I mostly listen to MP3/AAC files from my laptop/MP3 player and my only headphone amp currently is the budget Fiio E5 (will try to upgrade this to Graham Slee Voyager when my budget allowed...). Any suggestions would be most appreciated. Thanks