id say get a decent computer with on board video, and install the video card later (and additional ram) later
all these i found on newegg, for a grand total of 540
very good computer, but no dedicated video card, it does have onboard which will work, but wont game to well till you find a dedicated one, and when you get it, this computer will be very good
plenty of ram, and plenty of room to upgrade
plenty of data storage
good psu that should support any GPU you find
only thing it is missing is accessories and an operating system
as i said, you can find all this on newegg
MSI NF750-G55 AM3 NVIDIA nForce 750a SLI HDMI ATX AMD Motherboard
COOLER MASTER ELITE 335 RC-335-KKN1-GP Black SECC Steel ATX Mid Tower Computer Case
SAMSUNG Spinpoint F3 HD103SJ 1TB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
G.SKILL Ripjaws Series 4GB 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory Model F3-10666CL9S-4GBRL
CORSAIR CMPSU-750TX 750W ATX12V v2.2 SLI Certified CrossFire Ready 80 PLUS Certified Active PFC
ASUS DRW-24B1ST/BLK/B/AS Black SATA 24X DVD Burner
AMD Phenom II X4 970 Black Edition Deneb 3.5GHz Socket AM3 125W Quad-Core Desktop Processor HDZ970FBGMBOX
EDIT: i kind of made this on the spot based on previous builds (i have used the ram, the proc, a very similar motherboard (from the same manufacturer), the same case, 2 of those hard drives, and the powersupply, and none of them have had an issues (yet)
btw, when you upgrade to your new video card, the onboard one may seem useless, but i have fount it quite useful when trying to figure out problems if you have them (like when i upgraded my video card and the new card didnt work), or when troubleshooting the 'my computer wont post' problem