I want to buy a good pair of headphones in the field of gaming Which to go Razer Megalodon / or Barracuda with Asus XONAR-D1 (Sound card If you have other option's please let me know
Well, besides the fact the megolodon stinks (get the Logitech G35 if you go that route), it must be pointed out that USB headphones ignore the soundcard.
I generally recommend a soundcard (Xonar DX makes more sense then the D1 at this point) and a decent set of 5.1 speakers, but to each his own.
The DX is a newer model compared to the D1, but after looking at the spcs again, it looks like they are essentially the same otherwise, so both should be fine.