There are 2 builds in that list which one would you like us to review. Also both of them I would recommend a different hard drive. You can get 2TB 7200RPM drives for around $99. You could throw in a samsung evo 840 ssd to increase load times. I would not recommend a core 2 quad anymore with i5's or i7's out.
Motherboard: Asus mainboards are what I use...
CPU: I would be looking into the haswell or ivy bridge intel i5 for a budget gaming rig or possibly go amd 8 core.
Ram: you can get by with 8gb for most games and situations DDR 1600 is fine. Get 2 sticks so you can use dual channel.
PSU: Corsair or something similar with a single 12v rail try to give yourself 20% headroom so you are not maxing the psu out.
Video cards: nvidia 760, 770, 780 are all good, amd 7950, 7970, 280x, 290, 290x are all decent. It depends on your budgit. With nvidia you have the advantage of physx which in some games can matter.
The case is not a big deal but you want something with good airflow and a few fans, get at least 2 fans if not more...
The rest you can decide on, hard drives fail so have a backup plan or run a mirrored raid 1 or raid 5 etc. Maybe get an ssd to help speed things up.