I don't agree with most of what your saying... but i still appreciate your input.
1) There is a general consensus of what is neutral and which can (or cans) are closer to it than others. Its not just a random smattering. After all I think you can surely point out which cans are not likely to win a consensus on neutrality (edition 10 anyone?)
I'm unaware of such consensus, but if you say it exists...
The problem is that "flat" does not mean "neutral" - you can have a v-shape can that sounds "neutral" or "tonally accurate" because it makes a piano sound like a piano and a voice sound like a voice, but it doesn't measure like a board. Resonance can play into this as well.
As far as cans I'd add to the list that shouldn't be considered flat/un-colored:
Beyers (massive treble boosts)
Denons (massive mid-bass/bass boosts)
Sennheisers (treble boosts or mid-range drops or mid-bass boosts)
Grados (treble boosts or mid-bass boosts or extension issues)
Ultrasones (massive treble boosts and/or massive mid-bass boosts and/or screwy mid-range)
But having said that, how many of those SOUND flat to listeners? Or how many sound tonally accurate, while not being flat?
To give you an example, a few years ago a lot of people "discovered" the Beyer DT48 and got together and insisted they have the most accurate vocal reproduction of any headphone made (even compared to some of the items on your list, that were available then). But the DT48 are *not* flat and are *not* uncolored (their FR actually looks pretty screwy). That's an example of consensus telling us something is accurate without it having to be uncolored. Grados are a lot the same way. Instruments can sound "right" but the headphones themselves aren't "flat" or similar.
2) Most Grado's are purposefully colored and stray away from the herd.
So how is "neutral" not "colored" - or did you mean to say measures flat? In which case it's between Aude'ze, and a few 'stats (based on measurements from Tyll and Purrin). Most of the cans up there are "purposefully colored" - and "the herd" doesn't target anything universal anymore (because nobody aims at flat, you've got the "audiophile hi-fi" crowd trying to run 10-30 dB up at 10khz (is that neutral? is that uncolored?) and Aude'ze doing their own thing with an equally dramatic roll-off up there, and STAX and Koss that don't fit into either camp, so what's "average"?).
This can go round and round back to the "what is flat" argument which will eventually death-spiral down the drain. I'm also not the first person to mention Grado in this thread. :rolleyes:
3) Perhaps the koss 950 and stax sr507 is the most neutral. Still wouldn't be worthwhile putting it in here since so few have heard it couldn't win in a poll. Although I guess a greater representation that expected may be significant.
So the goal is no longer to find what's actually most "neutral," it's just a popularity contest.
4) Price has a correlation w/ quality, it may not be perfect or exact, but its there.
You already mentioned the Edition 10, do I need to say anything else?
I'm not trying to denigrate you, but I don't see how your question applies to what you want - in your original post you said this: "I mean the headphone that adds the least coloration (No extra bass oomph or treble, completely transparent)." But then you list off a bunch of currently popular cans that are inherently colored and non-flat, and refuse people telling you to include headphones that are inherently flat, transparent, etc on your list. Because they're unpopular. That's where I'm confused. I also don't quite get what you hope to gain from this, but that has never stopped me from participating in discussion about cans before - because after all, it's fun.
See this thread too:
http://www.head-fi.org/t/615781/what-high-end-phones-for-me-who-prefers-musicality-over-accuracy