Just picked these up off ebay for $75. They really hit the sweet spot in terms of sound signature for me and are exactly what I was looking for, particularly their linear and extended bass. I'd easily pay $200 for these, so no surprise people are buying loads of them on massdrop. The only downside is the headband, it really is uncomfortable and has no padding whatsoever. Does AKG not know how to design headbands or something???
AKG does know how, they just goofed this time and don't care for fixing it (goofed with K550, K545, and K551, too). Sennheiser also goofed with their HD6/7/8 DJ headphones when most of their product line is very comfortable for most people and well padded.
I put HD280 headband pads on my Sennheiser HD8 DJ and K545. It's cheap directly from Senn USA, and the headband pad wraps around the AKG headband and clips together, to need to remove or glue anything. The HD280 pad is thick and not too firm.
There are eBay sellers selling a button-on wool headband that a head-fier or two spoke well of:
Someone earlier in this thread said he put a Sennheiser HD600 headband pad on his headphone.