Nothing wrong with using EQ or DSP if it is perceived to improve things for the listener and don't let anyone tell you otherwise. That said, I usually do try to avoid EQ'ing when using headphones (Hardware tone controls are the one exception of course).. unless I feel I have to with a poorly mastered recording or overly coloured gear as I find it also brings it's own impurities to the sound, a harshness or even distortion in extreme cases... am I alone in this?
DSP is a tool I may use with certain tracks to try and add a bit of soundstage to a poor recording. If more music producers spent more time setting up for recording/mastering like they do for live bands (I concede that it's not feasible due to the very nature of pop music, sadly) we would have much less need for either of them . One track springs to mind, a particular recording of 'downstream' by ocean colour scene. It was recorded live in a studio and the Mic pick up points were obviously very well situated as the stereo width and instrument separation offer the listener a near perfect listening experience that I've heard, no DSP could ever get even close to replicating it. I gave my non-audiophile friend a listen to it through my TF10's, he was transfixed and listened to the whole song with his mouth open, afterwards was asking about my gear and how it could sound so incredible. I explained that my DAP, Neutron and TF10's were only a small part of it, it's just that they rarely record/master music that way these days.
It would be nice to hear of other other similarly well recorded tracks from fellow Headfi'ers?