Audio Technica ATH-M50
Beats by Dr. Dre
Bose QuietComfort 15
I used the above to compare against my Logitech G930's (wireless USB headset, so I did not use an external DAC with this). I listened to many .flac songs using all 4 of the above headphones connected to the E17, and then I listened to the same .flac songs on the G930's.
The winner: Logitech G930's. The sound on this gaming headset is so much more clear and I can hear so much detail compared to the M100's and ATH-M50's (and the other 2). The price for the G930's is $100. It's an all-in-one package. If anyone were to buy a DAC with headphones, you'd be spending $150+ on a DAC and then $300 on headphones. So for any "audiophile" who is looking for a good pair of headphones without having to buy all this other gear, please just go get the G930's. You will not be disappointed.
Maybe the DAC's are just boxes with air in them that just cause a placebo.