Hi -
Glad you found the site!
Here are my thoughts.
1) PSU - generally don' try to cheap-out on this component. A 500W would be fine for now, but you'll probably want to step up to the 650W if you do any overclocking or add a graphics card. Let us know what options you have for brand and model, and we can comment. Some brands have inexpensive models that most of us would not use in a custom build. I personally like to have a little more power than my minimum need. The PSU doesn't work as hard and I have overhead for future additions. (For my first build I had an NVidia 200 series GPU, 1 HD, and 1 DVD. I now have an NVidia 760, 3HDs, 2 SSD, 1 DVD, 1 BluRay. Couldn't have kept adding if I went cheap on the PSU)
2/3) RAM - 2x4GB should be fine. Your motherboard has 4 slots for RAM, so if you find that your machine is swapping lots of RAM to disk, you can always add more. By the way, if you're really using the RAM, 4x4GB will be slightly more optimal than 2x8GB, even thought the total is 16GB either way (I can explain further ...). Lastly, be sure that you are buying the correct dual-channel, DDR3 RAM. You can either purchase a "package of 2" or buy two singles - you're generally ok if these are the same type from the same manufacturer. To be sure, you won't damage your machine if you have mis-matched set, but your performance will be far less than optimal.
Your choice to defer on the graphics card is driven by your budget. I totally get that, and I would agree. It's better to save a wait a bit than spend all you have now and not be satisfied. For the price/performance point, I'd suggest two resources. Toms pulishes monthly Best X for Money. The articles typcicover CPU, SSD, GPU. Here's the April article on GPUs
http://www.tomshardware.com/reviews/gaming-graphics-car....
You may also want to check out
http://www.systemrequirementslab.com. This site has a reference for almost every game out there. It provides the setup for what your PC needs to meet the minimum requirements as well as a "recommended" configuration.
You haven't mentioned an SSD in your configuration above, just wanted to check to see if you are including one in your build. If not, you should consider it. SSDs make your whole system more responsive and generally faster. There's a bit more configuration you need to be sure happens when you install your OS, but it's WELL worth the extra couple of steps.
Does this help?
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