I purchased the headphones I have for different purposes, so it's easy to rank them:
Sennheiser HD650+Zu (Critical listening, ultimate fidelity, balance & refinement)
Grado SR-60 (First quality headphones I got, chosen over HD600 and AKG501's, great sound, great price/perf. ratio, and no amp needed)
Shure E3c (Ultra portability + isolation)