It would last around 5 years then some new incredible software would come out and he couldn't use it. I would get it or use other xp product you have and then get vista in about 2 years. Don't get it untill the bugs are worked out.
You guys talk as if I am only going to be using Media Center. The computer would be a waste if thats all I would be doing. I forgot to mention that I will be using a recording program called ProTools which requires a high performing computer, and along with it, a program called Reason which will produce beats. So, it will be used for home entertainment, music production, and games (probably once a month )