Agreed phoenixdogfan. I remember when I trialed the average profile with my HD650, I was already very impressed by it. I later sent my HD800 from Canada all the way to Latvia for an individualized calibration, it came back and the sound was perfect in every sense to me.
Here is my advice to people out there:
Try the plugin, the average profiles are not as accurate as the individualized profiles, but it will tell you if the reference curve works for you. If you like it, you should consider getting an individualized calibration, with all the attendant suggestions below.
Buy a headphone with low distortion, good power handling, and a reasonable price. I recommend the HE400S: http://www.innerfidelity.com/images/HiFiMANHE400S.pdf
It's inexpensive at $299 USD, has low distortion and strong power handling evidenced by the THD+n chart at 90dB and 100dB. Its FR is linear and relatively absent of steep peaks and valleys. It will take an EQ very well.
Send your choice of headphone to Sonarworks for an individualized calibration, the cost of the service itself is almost nothing as it includes return shipping, I don't think they even make a profit on this. Majority of your costs will be shipping on your end.
When you get your headphones back, you'll receive a profile that is channel matched and calibrated closely to their reference curve, and in my case I also requested and received charts with measured THD and a CSD waterfall plot. That is very useful and I couldn't get this anywhere else.
Option B:
Get the pre-calibrated headphones from Sonarworks directly, this will save you money and time, but in my opinion planars will take an EQ best, and they have no pre-calibrated planars. You could argue that the advantages of planars are marginal, and almost entirely in the reproduction of low bass, but I feel it is worth it especially with a capable and cheap planar like the HE400S. People may ask, if even cheap planars are so good, why did I get a HD800. I chose the HD800 because it matches or exceeds planars in everything except power handling, and is also light and comfortable, however it costed $1300 new, while the HE400S manages to come very close at only a small fraction of the price. I don't think any dynamic exceeds the HE400S in its price range, although the Fidelio X2 does come close. The HD650 is also comparable but costs more and suffers from distortion in the lower frequencies.
Now with all this said, I will just ramble on a bit more about my personal experiences with audio. *Warning stream of consciousness ahead*
I have owned and trialed high end headphones, and mid end headphones, this goes for IEMs as well. I feel that a portion of this hobby has become like alchemy; people try and buy endless combinations and never know what they will get, maybe they will transmute gold, I don't know, but at least it is fun for some. I don't mix and match multiple headphones, DACs, amps, and interconnects because in my opinion the results are dubious and it will cost me a lot of money. I only have one main system for each living area, and I am only concerned about the output. I think Sonarworks is perfect for this, you get reproducible results across a wide variety of headphones, you have a free trial and you know what you get in advance. I have been using the individualized profile for more than a year, and I have been completely satisfied by it. The only thing on my mind now is to get the rest of my headphones calibrated.
If only there was a solution like Sonarworks for IEMs and smartphones, I would be over the moon. A good IEM with a single full range dynamic driver, calibrated, would be better than dealing with the wild goose chase that is the IEM market right now. However, the IEM market is fragmented, too many models to measure, the IEM compensation curve would be different, and the professional market is non-existent, leaving only quibbling audiophiles, moreover there are no Android players that can host VST plugins that I know of, nor is Sonarworks a media player. So it's a pipedream.