Case: Rosewill CHALLENGER Black Gaming ATX Mid Tower Computer Case, comes with Three Fans-1x Front Blue LED 120mm Fan, 1x Top 140mm ...
Model #:CHALLENGER Item #:N82E16811147153 $55
Mobo: ASRock Z68M/USB3 LGA 1155 Intel Z68 HDMI SATA 6Gb/s USB 3.0 Micro ATX Intel Motherboard Model #:Z68M/USB3 Item #:N82E16813157270 $85
Ram: If 4gb: G.SKILL Ripjaws X Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory Model F3-10666CL9D-4GBXL
Model #:F3-10666CL9D-4GBXL Item #:N82E16820231425 $27. If 8gb then mid $40 range
Video: Here's where you need to make a decision. If you want good gaming peformance you need to get to the 6850 or 6870 Here is one example of a 6850 for $150: SAPPHIRE 100315L Radeon HD 6850 1GB 256-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card with Eyefinity
Model #:100315L Item #:N82E16814102908.
My suggestion as far as Graphics is if you don't want to spend any more money, go with the 6790, which is only $130 but if you want better performance in games, as said before, go with the 6850 or 6870.