For me, it was (ashamed to say it) the Sony MDR-V700 DJ cans. I got them at the Good Guys (RIP) for like $200, and my girlfriend thought I was totally insane to spend that much on them. I still have them, broken pivots and all. The first time I tried them with my Sony Discman, I nearly blew my head off, they were so loud. Many many hours of sitting around with the bong, my CD collection, and these strapped to my skull, I thought "wow, these have to be the best headphones EVER!", but now i use them to A/B when I want a laugh. Form there, I got some Sony isolation buds (don't remember the model), but they were like $140, which I thought was really steep, but I had to have them. I was happy for years with this setup, but finally my boss recommended I get an amp (I got a Total AirHead) and some Etys and I haven't looked back since. Curse you, world of hi-fi!