So, I would up with a pair of Shure SE315 over the weekend. I left my Audioengine D3 plugged into my laptop at work, so I am left with only my new Lumia Icon to power the headphones while listening to Beats Audio (high quality audio on 14 day trial). The sound is bitching. Best headphone experience I've had thus far.
I thought if the SE315 sounded this good with a phone, then it must sound even better with my Win8 laptop with Jplay (ultrastream and directlink), Fubar playing FLAC files and Audioengine D3. But, the sound was actually worse with the laptop setup than with the phone set up.
Another note, my other headphone is a pair of JVC HAFXT90 which I think is a marvelous headphone. On the laptop, the SE315 sounds notably clearer and less hollow which I didn't think was possible as the JVC is already a very very clear sounding headphone. On the Icon, the Shure pulls farther away from the JVC. Wider sound stage and more dynamics.
So, my unexpected observation so far is that the laptop with higher res file, more pricey hardware and software is losing out to a phone. OTOH, i do find that Windows portable devices are sounding very good. I have two other Windows tablet devices, and both sound very good either analog or digital out.
The Surface sounds much better than my Dell desktop via usb digital out. And, my Toshiba Encore's analog out is very superb. Have to compare the Encore's analog out to the Icon's after I get home.