Here is another opinion if you want. I don't use the EQ personally because with it on my audio sounds really bad. The presets as someone else has mentioned are crap but that isn't why I don't like the EQ. With the EQ turned off my music sounds like heaven to my ears.
Therefore the sound you get is largely dependent on the type of headphones & quality of music files you listen to.
Just a suggestion, if you are still dissatisfied after tweaking the various options maybe it is time to upgrade your headphones. You'll most likely be amazed at the difference.