This has been my system for a few years now. I did have a traditional hifi of CDP, amp, speakers with a headphone amp and some Grados, but I gave all of that to a friend in need, keping the headphone amp and cans. Various house moves and compromised speaker positioning meant a head-fi based system made sense. It really took off when I got an ipod for Christmas and then one of the original invites for Spotify. All my CDs are in the loft and all my listening is off itunes and mainly the internet, including You Tube and Grooveshark.
My headphone collection is mainly AKG
and various vintage headphones
I spend hours every day trawling the interent for new music and posting drivel on forums.