Depending on what he's going to do with it, I'd go with an i5 instead.
And modular power supplies are really nice, like emo said.
Do any am3+ boards support usb3 without 3rd party stuff?
I have an am3+ MSI gaming motherboard with USB 3.0 right on the body, so I know they will work that way, now adding USB 3.0 to the plugs? I'm not sure. I know USB 3.0 VIA PCIe will work, as for the USB port plugs on the board, I don't know, as my board for whatever reason won't run the 3.0 ports on the front of my case ( I may have to take ahour or two with the guide book, and dig around at it. when I remember where I put the book.)
as for the rest of the setup, if he's gaming, Realistically a phenom series Processor (still am3+ compatible) will run about as well, (or as is the case with the Phenom II x6 1100T) will run better in some cases, than any fx chip, for less. Another good route to look at is any i5 xxxxK series chip. if he's gaming, you could go down to phenom (saving a few bucks) and upgrade the videocard to a 7870, or even pick up an SSD for the OS, and a 750GB HDD for games/programs/storage.