They did a release of the New Slim model. There's a lot of comments on the new system, but you should still be able to find the old slim model. Check out some of the
youtube videos to see which one you like or your kid likes better.
They also restructured the pricing, it mainly has to deal with the hard drive size. More and more full size games are being released on PSN, so that could mean 4gb or larger game downloads. Playstation Plus is also a great addition, they offer discounts on the PSN network as well as free games every so often. A handful of the games we have are free with PSPlus. Plus they offer a free Cloud save for game saves. It makes it much easier to transfer to a new harddrive, or access your game save from another PS3.
Upgraded to the slim PS3 little less than a couple years ago, and the 160gb really wasn't efficient. Recently put in a new 1tb hard drive (it uses a standard laptop harddrive), and finally downloaded all the games, it's over 400gb of games. Granted this is 6 years worth of purchases. Transferred all the game saves to the cloud, and then put them onto the new harddrive.
Shooter games are also using the Move for more accurate shooting. A lot of people like this feature. But completely optional device.
Playing online is free unlike the Xbox, so you don't need anything there. Although a bluetooth mic would be a good addition. I don't find the online community quite as bad as what's on xbox live, but personal opinion on that.