Sennheiser HD600s: Ears get hot after extended use, (though don't think anything except the K1000s will be much better), and I don't have the money for a cable upgrade right now (don't really have a problem with the stock cable's sound quality, but don't like how easily it gets tangled up).
Second pair of Sony MDR-EX71s: Just plain bad. I liked my first pair (which suddenly broke one day), I hate this pair. I get headaches from the sound... comfortable though.
Audio-Technica ATH-CM7s: Having trouble readjusting to using earbuds instead of canalphones - I'm constantly fiddling with them since I feel like they're going to fall out. Comfort is only OK - the cut/indention on these is annoying, though if I rotate the stalk completely downward (or the driver completely upwards), it's not a problem. As for the sound... bass is lacking, which is more or less expected, but everything else is fine for portable phones. And I can't say these are worth the $130 they go for on AudioCubes.
Sony MDR-D11 Eggos (out on loan): For the price that I paid for them ($6), I can't fault them for anything. The pleather pads are worn out, but it's been nearly 7 years. As for the sound... certainly better than anything else I've heard that's less than $10, and better than most that's less than $40 (I'm not all that big a fan of the KOSS portables - I'd rate them about evenly) .
~KS
