My son is 5 and he had been playing the Vtech portable system which also allows you to hook up to your TV. My wife and I didn't think he was ready or mature enough to take care of an expensive unit like an XBOX 360, Wii or PS3 so we decided to go with the PS2 (slim).

I used to have a PS2 before I was married but sold it at a garage sale once my son was born. I just didn't have the time to play it anymore. Now our son was showing an interest in video games and I loved playing them with him. The library of games available for the PS2 is immense, and each of them is very affordable. They're still making games for this console for crying out loud (ex: Lego Batman).

We limit his time daily on the console but I think he has shown enough maturity and it has retained his interest from day one. I'm thinking Santa may bring an XBOX 360 down the chimney this year (I hope, I hope). The game on the Wii are pretty lame and the PS3 is just too danged expensive - and from what I saw from Microsoft's "Project Natal" (do a youtube search), it is definitely something everyone is going to want in their living room.

So again, in a nutshell - if you're looking to make a small investment (I bought our system used at GameStop for $79 in excellent shape) - the PS2 is the way to go.