I would suggest looking at NCIX weekly sales and built your computer base on those parts. Most of the time you can find pretty deals on almost all the items you need to build a decent PC.
For example:
NCIX Gaming Bundle Deal AMD Phenom II X6 1090T & MSI 790FX-GD70 CrossFire DDR3 Motherboard
http://ncix.com/products/index.php?s...s&promoid=1026 259.99
Antec Three Hundred Mini Tower Gaming Case 300 ATX 3X5.25 6X3.5INT No PS Front USB & Audio
http://ncix.com/products/index.php?s...c&promoid=1026 29.99
G.SKILL F3-12800CL9D-4GBRL Ripjaws PC3-12800 4GB 2X2GB DDR3-1600 CL9-9-9-24 Core i5 1.5V Memory Kit
http://ncix.com/products/?sku=42745&...l&promoid=1026 44.99
Western Digital WD20EARS Caviar Green 2TB SATA2 3Gbps 64MB Cache 3.5IN Hard Drive OEM
http://ncix.com/products/index.php?s...D&promoid=1026 69.99
OCZ B-Stock Refurb Elitexstream 1000W ATX12V 24PIN ATX SLI Ready Power Supply 120MM Fan Black
http://ncix.com/products/index.php?s...y&promoid=1026 69.99
XFX Radeon HD 6950 800MHZ 2GB 5.0GHZ DDR5 2XDVI HDMI 2x Mini DisplayPort PCI-E Video Card
http://ncix.com/products/?sku=59610&...anufacture=XFX 253.77
LG GH22NS50 Black 22X SATA DVD Writer OEM
http://ncix.com/products/?sku=40435&...%20Electronics 25.99
This will last you a few years. Also you can do upgrades here and there if you need to (More RAM, Add anohter HD and so on). You can even add some In take fans change out the Heatsink.
That I would say is a pretty decent setup. Of coz I just pick off the items that's on the sales page. If you have time you might want to look at it in details on the web site and you could sale your self a bit of money.