Just a cheap pair of Sony MDR-V150s. Eventually I will get some MDR-V700DJs. A friend of mine has a pair and they kick ass, all the other headphones I've ever tried come no where near to their clarity and bass reproduction, its almost like having a damn subwoofer on your head.
EDIT: They are also unbelievably comfortable, you can easily wear them from the time you wake up till the time you go to bed and not have a sore head. And I just looked them up on amazon: 50mm drivers that deliver bass down to 5hz. Sure, the eardrum is, on average, only responsive down to 20hz but you can FEEL 5hz.