Looking to get him an average 7 series card, when they come out. Probably a 7770/7790, depending on the prices and/or if I buy from Amazon I might look at a 7850 (it the price is close to that of the 7790)
Motherboard - not too sure yet. Might get the cheapest z68 chipset I can get or a decent p67.
The fact that you are trying to buy a psu for a card that hasn't been released yet is a hard thing to do , you don't know what the power requirements are for the cards yet so you would be guessing. If you knew what the psu requirements were and you could use the 620w Antec then I would go with that one , I don't see the 650w being required for one card but it is also a quality psu and you would not be making a mistake by getting the Corsair 650w. If by some chance you wanted to go 750w I would go with either an Antec or Corsair.
A Z68 chipset board would be a better choice in motherboard.
Either way it's a low end card and he has a low power cpu. So even if you factor a new 77w Ivy Bridge quad core in the future and maybe a video card upgrade after that, a 620w will still allow those upgrades.
The Radeon HD 7850 (95W), Radeon HD 7790 (85W) and Radeon HD 7770 (90W) are all rumored to be designed to use less than 100 Watts.
If you're going to be using a single one of these cards a 400 Watt or greater power supply with a combined +12 Volt continuous current rating of 24 Amps or greater and with at least one 6-pin PCI Express supplementary power connector will be enough to power that system.
If you're planning on running two of any of those cards in 2-way CrossFireX mode then get power supply with 500 Watts or greater with a combined +12 Volt continuous current rating of 34 Amps or greater and with at least two 6-pin PCI Express supplementary power connectors to power that system.
In case you're wondering why no one has suggested the GX-750, it may be because the very similar "little brother" GX-650 was summarized by HardOCP as being a "polished turd in a box."
The bottom line is particularly harsh, but deserved: http://www.hardocp.com/article/2010/11/22/cooler_master...