Here are the headphones I have and rotate in between. Not as serious as some others but serious for me.
I've got Sennheiser HD580, BeyerDynamic DT48 25 ohm and
AKG K701 with Balanced Fat Pipe Upgrade from Headroom.
With these headphones I use the headphone jacks on my Accuphase C200, Grant Fidelity DAC-09 or an Einar Sound headphone amplifier.
One really serious set of headphones that has caught my eye is the BeyerDynamic T5P. I just can't justify the money for this kind of headphone but it is cool nonetheless.