So far you have a good basis for a budget build.
- The FX6300 is a good microprocessor for a budget build that can keep up with system upgrades later on. Plus, when you use AMD's AM3+ socket, you're allowing for upgrades at least up to their next upcoming generation of CPU's. I think between the long-term socket support and good price-performance ratio that this makes the FX6300 a budget beast. $120
- The 760G chipset is really going to limit this build. While it will work, I would personally save up a little more money and go with a 990FX chipset. If He does not want to save up a little more for the 990FX, then I would say at the absolute minimum, go with the 970. My personal budget board recommendation would be:
http://www.newegg.com/Product/Product.aspx?Item=N82E168.... $110
- The video card is a fine budget card. Plus, if he does find that later on it is hindering his performance he can always upgrade. It is a good overall card in terms of real-world performance versus price. The 1GB memory and 128-bit interface will really hinder the card, but he should be able to get away with respectable settings in a lot of games, just don't expect do power a multiple monitor configuration with this card unless it is just for basic productivity. $100
- Hard drive is good enough. Again, this is something he can easily change later on if he really feels like it is holding him back. So, I wouldn't worry too much about it for the initial build and it will give him good enough performance overall. $60
- Memory is fine. I'd personally recommend saving up a little more and getting 8GB instead of 4GB, but the 4GB should be enough if he isn't playing super intensive games or a heavy power user. $40
- A case is a case. As long as it supports the size of your motherboard and has room for the components you want to use, has good enough airflow, then it is all subjective. $40
- While this power supply seems to get good enough reviews, most of them are based on superficial testing or short-term use. I personally would go with a Corsair, Seasonic or XFX PRO series power supply to make sure my components are safe, stable and always getting sufficient clean power. I'd probably go with
http://www.newegg.com/Product/Product.aspx?Item=N82E168.... $90
- Optical drive is fine. $20.
New Total: $520 + shipping.
Yeah, it puts you $20 + shipping over budget, but it would be worth it to save up the extra ~50 bucks and increase the quality of the build by a large margin. The extra money really lets you build on a solid base that can be upgraded upon later to achieve the desired performance. You will pay a lot more than the $50 down the road by cheaping out on key components now.