So, the X7 LE is really going to be MUCH better for us Headphone gamers, than the regular X7?
As far as I can see, besides the differences in limited-edition status, case color, power supply for the speaker amp, and lower-than-the-already-low output impedance (which only provide a benefit if you game with the most ultra-sensitive in-ear canalphones), there is no difference for headphone gamers and the extra $100 is better spent on a few games.
The only difference to the headphone section is the X7 has ~2.2 ohms output impedance (already very low) while the X7 LE has ~1 ohm output impedance. Are your headphones less than 16 ohms impedance? If not, the X7 and X7 LE will perform exactly the same.