That is a good reasonably balanced build.
If the specific games you play, can use more than 2 cores, only then perhaps a quad would be better.
But, few games actually use more than 2 cores.
Read this article on <$200 gaming cpu's. Yhey used a GTX480, not so different from the GTX560.
http://www.tomshardware.com/reviews/best-gaming-cpu-core-i3-2100-phenom-ii-x6-1075t,2859.html
On the other parts of the build, here are some thoughts:
I happen to like Intel motherboards, but I think you might want a Z68 based motherboard to preserve your option to upgrade to a overclockable cpu in the future. It need not be more expensive, like this ASRock Z68M/USB3
http://www.newegg.com/Product/Product.aspx?Item=N82E16813157270
If you love the case buy it. period.
Otherwise, there are cheaper options, and smaller options.
The Antec 200 is $50 with free shipping:
http://www.newegg.com/Product/Product.aspx?Item=N82E16811129074
The antec illusion is $70 including free shipping(cases are heavy and expensive to ship)
http://www.newegg.com/Product/Product.aspx?Item=N82E16811129066
A great smaller M-atx option is the case I use, the Silverstone TJ-08E at $99 or so + $19 shipping
http://www.newegg.com/Product/Product.aspx?Item=N82E16811163182
Stick with top quality psu's, like Seasonic, Antec, XFX, Corsair, and PC P&C.
de5_roy named two good ones.
Sata hard drive prices are crazy today.
Consider a 80gb SSD for the OS and a handful of games. Add a hard drive for expansion later when hard drive prices return to normal.
Look for intel, samsung, and crucial in that order. Intel has been having rebates in the $1 per gb range so look for them.
I think they are clearing inventory in anticipation of their 520 series launch.