HighwayStar: The Cardas cables for the HD580/600s are replacement headphone cables. Instead of the cheapo cable that sennheiser uses(the cable that goes from your amp to the headphone), the cardas is a high quality one. The problem is, that it's terminated with a 1/4 inch jack. The output on the d25s is 1/8. I don't want to constantly swap cables, and I won't, since I'm afraid of degrading my jack on the hd580s.
jpelg: you bring up some very good points. The problem I have with buying the d25s is that it falls between my 2 rigs. I mean, I wouldn't be using my hd580s with it if I got the cardas. If I didn't get cardas, I would probably get the d25s, if only as a cdp to take around the house, deck, etc. So, I'd be basically buying it to use with ksc-35s. Which, personally, I don't think is worth it. The one thing holding me back? I've just fallen in love with the player's looks.
Please, someone, convince me that I DON'T need the d25s. PLEASE!
Once I'd get the cardas, my rig would pretty much be done. I mean, one day, in the future (read: college, after high school), I might consider a dac or source upgrade. But not now.