I'm going to be pairing these with an O2 DAC/AMP that I just got. As the title says, nominally/optimally my maximum is 350-400$. I'm willing to go over if there is a very good reason (but only if there is a very good reason). I'd like some bass, but that takes a backseat to making sure the rest of the range doesn't get muffled. I tried out the Sennheiser HD598's at Best Buy but did not find them to be quite what I was looking for. Some of the sounds felt a bit muffled and it did not sound like they would be good with a violin (I listen to a decent amount of David Garrett). I also like rock and techno (not dubstep) all the way through Touhou music, Nightwish, Dream Theater, etc.
For comparison, the speakers that I am using right now (and I'm quite happy with them) is a pair of Mordaunt-Short Aviano 2, with a Topping TP20MK2 Amp. You'd be hard pressed to find any frequency response graphs on them, so let's say that they are similar to (probably a bit better than) Aviano 1's, but with a more well defined bass component, which are in turn IIRC similar to Cambridge S30's. So, something that would sound similar to these would be nice.
Oh, and it would be a plus if I could drive them half-decently without the amp, but that's about it. I've looked at AKG712Pro, HD600, HE400, etc. Not quite sure what to choose, or if there are other options.
TL;DR hear stuff as it is meant to be heard. Oh, and it needs to be very comfortable. I have a pair of HD280Pro's, but I find them to be very uncomfortable to wear, so I've just given up on using them in favor of my speakers. Looking for best value.