Nothing beats my K-1000 + subwoofer combo. Having variable bass level in the first octave is a delight.
Second choice is the Sen HD600 with an digital EQ and a good clean amp. The bass is amazing, with bottomless extension and amazing speed. The absense of overhang does take some of the fun out of it, though. With the EQ, I am also in love with the AT AD10 and the AT W100.
Unassisted, I think the Ultrasones are champs (I have the HFI650). They use a resonator that beefs up the deep bass. Unfortunately they have a boosted treble as well, and the stock pads are a pain.
The Beyer DT250-250 can also produce very satisfying bass without EQ, if they are working right. I had to rework the right side of one pair due to an assembly issue which robbed them of deep bass. A little known secret is that these cans are very tuneable for bass response, but you need some simple test gear to know where you are at with them. They are very sensitive to minor changes, and you can overshoot.
What not to get: the Sony F1.
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