Yup in all seriousness I wouldn't swap back to the HE500's. The 500's are brilliant at what they do, but they just don't have the imaging and soundstage for big complex peices. Same goes for the LCD2's for that matter. The K's are really special in that respect, the way that you can pin-point instruments in an orchestra for e.g. The newer K's don't seem to have that thin-ness in the mids that my 702's used to have. Not bashing the 702's here either because I had them for a year and thought they were brilliant too. Only I seem to be enjoying the AKG sound a lot more this time round. And I suppose that has to say something when I've spent the last 8 months listening to 2 high-end orthos. I thought that I would never be able to step down with headphones again. But the K701's are not a step down, no way. They are only a lot cheaper!
The orthos have a certain charm that makes pretty much any recording sound good. This is almost like wearing rose tinted lenses, you know its gonna sound good before you put them on your head. But its not realism. A headphone such as the k701's gives you the true picture, good or bad. Admittedly it makes you more selective in regards to recordings, but when the recording is good then the sound is a true hifi experience.
I've read quite a bit of this thread today and one poster stated to not use a warm source with these and to let the music provide the warmth if it is there. I couldn't agree more! I think the whole point of owning a headphone such as the K701 is to appreciate the linearity. It was designed for accuracy, so don't colour it!