ouch
It hurt me to see those, physically. Sorry to say that, we all want to do well in domaining, and want you to do well also.
enterxbox.com is the only one I see that's interesting enough to either develop or try sell, it's a step in the right direction... EXCEPT that you're playing with a trademarked name here, so all must be done with careful discretion (or not at all). I myself don't reg any trademarked companies like xbox as domain names; it's labelled a 'bad faith' registration since you're trying to profit from another's trademark and most of us stay away from it, especially due to high probability of a c&d (cease and desist) order. However, a lot of people still flock towards doing it even when they know this... my domaining biz-partner did this and loves it... she has xboxbuzz.com, xboxchicks.com, xboxkids.com, xboxies.com, pepsilicious.com, etc., and no c&d's yet.
You'll have to make your own decisions here.
Spend a lot of time looking thru the other forums at this site, and spend some time in the dn discussion area. And there are some great primers on how to choose good dn's, and how to research them (Overture, Namespinner, TESS trademarks, Alexa ratings, and many other names you'll learn along the way). If you want to consider the xbox name, spend some time in the legal threads. There are a LOT of xbox names parked at Sedo, which you could do... yours actually is one of the stronger ones.
Despite, and based on, all the above, I'll try make a valuation of it:
reseller (that's us - domainers) = up to but no more than xxx ($100), if someone likes it... because it really is a decent xbox name.
If you park it at Sedo or somewhere else that parks pages for sale/auction, I'd put a minimum bid of $500 on it, 1,000 at most.
Good luck, happy domaining
