Good question. I think it depends on music you're listening, and price you're willing to pay. For now my faves are from Sennheiser (affordable HD-555 for general listening and HD 25 SPII in some cases) and Koss Porta Pro on the road.
Don't buy anything until they've been on your ears in a shop and you've done some research as to their quality/usefulness for what you want to do, and overall.
Without faith nothing is possible. With it, nothing is impossible.