If he already has a PS2, and he doesn't own any previous Nintendo, or X'Box consoles; odds are, he would want a PS3.
All three consoles are pretty damn good; it really depends of what games he likes to play. The X-Box 360 and the PS3 offer a very similar range of games, but the PS3 has the smallest range of great games available at this stage, because it's still early days, however, some would agree that it has the most promise out of the three consoles.
The Nintendo Wii is a great and innovative console, and it was my first choice, but it’s not as popular with younger generation gamers, in fact, many younger gamers tend to shun it, and at the end of the day, the last thing you want to do is spend hundreds of dollars on something that he will think is lame, and never want to play, regardless of how good it really is.
My advise would be, if you want to get a better gauge of what he’d be after, maybe check out what games he currently owns for the PS2, make a list, and go to your local games store and ask them which console would offer a similar range of games, or if there is a particular console that offers all the newer releases of those games.
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