As mentioned by others, there's no such thing as 'the best settings'. It's entirely personal - some like EQ, some hate it. Some like the extra oomph of additional gain, others can't stand the extra distortion it might add to their setup. And let's not forget about our ears - pretty much a given that no two people will hear the exact same nuances from a given setup. That said, these are the settings I use:
Beyerdynamic DT770 Pro 250 ohm - gain 6, bass +4, treble +2
Sennheiser HD800 300 ohm - gain 12, bass +8, treble -2
Shure SE530 IEMs - gain 0, bass +2, treble 0
Volume is almost always between 25 - 35 for the E17 alone and 1/3 to 2/3 on the volume pot when docked on my E9.
Edited by AgentXXL - 1/1/13 at 1:21am