Okay, I've ordered.
I have the K81DJ, and it's a fine headphone that works particularly well with the sound of my 5.5g iPod; I felt I needed a sound with a little more sparkle, however, leading to my search. The Yuin is said to have fine sound, but I think I want to stay away from anything that might fatigue my ear canal, given the irritation I sometimes feel with in ear devices.
The Sony is the class of the group, and despite missing a recent sale, the price is still inflated beyoond its value. But it looks like the ES7 has everything - good sound, nice looks, a sparkle, and rave reviews.