On one hand, I know people older than you who unashamedly love Xbox. On the other hand, I think they're too old for that.
And whatever you decide, make sure you have a good place to hide it before you buy it.
Well, I'm 32, a former Marine officer, rapidly approaching being a lawyer, and have a wife and two kids, yet every once in a while I get sucked into a loooooong night of playing videogames (Rogue Spear, Steel Panthers, etc.) on my PC. But of course playing on my PC lets me deny that I have a problem; it's just an occasional diversion. An Xbox consitutes surrender--it's like admitting you're a full-blown junkie.
What most guys our age do is wait a couple years, then buy these sorts of toys "for the kids." What a great scam!