I tried to dig some stuff on it. Thought it would be a Roman numeral, but it's an invalid format. XVXX isn't an acronym for anything. Only 33k results for that exact phrase being used on indexed Google pages. There are only 2 extensions taken (dot com and your dot net). And to top it off; myself, I'm not a dot net fan.
The only plus I've found for it was that it has 6600 exact searches on Google. The downside to that is that it appears it's adult oriented with the other similar searches of "xvxx free" and "xvxx videos"-- but who knows exactly what the other thousands are intending to search for.
From me: reg fee unless developed into a possible adult gateway that receives some sort of traffic or other type of minisite.