EQ and other tools can really make a tremendous change for a headphone. Here is my EQ setup for LCD-2, HD600, EPH-100 and Vsonic GR06.
I suggest finding you own headphone graph here or some other place and go from there. As we all find out eventually there can be a big different with what the graphs say and what what we actually hear with the headphones on, but the graphs is a good blueprint to start with.
In the case of the Vsonic GR06 EQ can transform a solid but slightly muddy and lacking some clarity type 100$ performer to really a high end headphone. I wish the soundstage was a bit deeper and the sound slightly less grainy, but other than that it's one of the best all-round headphones I ever tried. Anything with instruments is spectacular, especially classical.
I'm using J River Media Center.
First I lower the bass with EasyQ. If I'm using crossfeed this is not necessary with some genres.

Then I use a plugin called TB EZQ that really do the magic refining the sound for the GR06. It's like these two products where made to complement each other. The increase in clarity, detail, imaging and soundstage is by quantum leaps. This is working great with all the other headphones mentioned here too, and will do so with any headphone that is lacking clarity or treble refinement in my experience. Sometimes its enough to just move the dot a tiny bit to the right or add some warmth to make the sound just perfect even with a perfect EQ curve. This is a great tool to increase clarity without adding too much harshness.

And last but no least I use J Rivers built in Effects that increases the soundstage size and layering beautiful with this headphone. Not all headphones respond as good as GR06 to these settings. This is open to play around with or avoiding completely.
Don't miss J Rivers built in crossfeed called Headphones. It blurs some detail especially in the lows, but with some 50's, 60's and 70's music with very separated channels it's a must to use at least use the subtle setting for a more natural sound using headphones. I find this to be the best crossfeed I've tried so far, and I have tried a few of them.
Don't forget to lower the volume by -10 dB in Parametric Equalizer to avoid clipping

LCD-2:

HD600

EPH-100

Hope this will prove helpful.
Edited by Sweden - 9/8/12 at 8:13am