Shane D
Headphoneus Supremus
So, you essentially want every headphone to sound the same. Or at least similar.While it's not a must, it certainly helps a lot especially if you know generally what your target FR curve looks like. When I EQ, it's not necessarily that I want everything sounding the same but just that I want to make up for clear tonality issues which especially present themselves when certain instruments (especially noticeable with brass for me) just sound wrong.
I don't get that. My favourite three headphones are Grado GH2's, Focal Elex's and CFA Cascades. They sound wildly different and I like that. I will not bass up the Grado's or bass down the Cascades. I enjoy the differences.