Increase the bitrate of the graphics card. Don't get DDR5. The difference between DDR3, 4, and 5 are negligible with the games of today (the best ones).
The case seems slightly ridiculous. Also, your mobo is ridiculous. How much are you planning to upgrade because your mobo can do more than you'll need in terms of upgrading non-mobo parts.
Also, what are you using your computer for?
If you are planning on gaming, the next upgrade would be to upgrade your HDD. Either get a solid state or do some raid configurations.
If you are gaming, you won't need a quad core. It's overkill and most games don't even use two cores, let alone four.
http://valid.canardpc.com/show_oc.php?id=789681
I has a Phenom II X2 550 BE