This is a similar to another build I made for another OCN member but I changed it around to Radeon graphics and made it around $900 bucks. This build is really powerful for the price.
MB: ASRock P67 EXTREME4 B3 LGA1155 Part#:MB-P67X4B3 http://www.superbiiz.com/detail.php?...TX-Motherboard $159 shipped
or if you want to save money and don't need SLI/Crossfire (having 2 graphics cards) ASRock P67 Pro3 B3 LGA1155 Mfr Part Number: P67PRO3 B3 http://www.superbiiz.com/detail.php?...TX-Motherboard $131.99 shipped (Asrock is part of sub-brand of Asus, they make really good mother boards for cheap)
CPU: Intel 2500K BX80623I52500K you can get this for $180 if you have a microcenter store near you (instore only). If not then its $215 on newegg and superbiiz http://www.newegg.com/Product/Produc...-072-_-Product
HD: Samsung Spinpoint F3 HD103SJ 1TB 7200 RPM 32MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive, This is the best hard drive on the market. I only order hard drives from newegg because they package their hard drives well. http://www.newegg.com/Product/Produc...k=samsung%20f3
Case: Cooler Master CM 690 II Advance ATX Mid-Tower Case (RC-692-KKN2) http://www.amazon.com/Cooler-Master-...4966684&sr=1-1 $90 shipped. This is another great case but has no fan controller and is only a mid tower.
PSU: Corsair 650TX v2 http://www.newegg.com/Product/Produc...-020-_-Product
CPU cooler: Coolermaster 212+ RR-B10-212P-G1 $30 http://www.amazon.com/Cooler-Master-...4967131&sr=1-1
DVD drive: Samsung SH-S222A/BEBE 22X DVDRW Internal Drive (Black), Bulk http://www.superbiiz.com/detail.php?...ive-Black-Bulk
GPU: HIS H695FN2G2M Radeon HD 6950 2GB http://www.newegg.com/Product/Produc...-368-_-Product
or if you want to save 90 bucks get the Sapphire Radeon HD 5850 XTREME 1 GB DDR5 100282XTREME which is slower but still very good. http://www.tigerdirect.com/applicati...805&CatId=3669
Your budget is $900 and with that budget you'd get much more performance out of a 2500k. Building a phenom II x4 rig right now is a waste of money imo.