Help with Gaming Build at around $600 - $700

A trial build

CPU/motherboard combo- AMD PhenomII x3 720 and Asrock 780G crossfire capable mobo 8X-8X DDR3 $199
http://www.newegg.com/Product/ComboDealDetails.aspx?Ite...

RAM - 2x2 GB OCZ DDR3 1600 7-7-7-24 $74
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

GPU- HD4850 XFX $109 (or substitute a 4770 at same price)
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Case - Antec 300 $55
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

PSU - Antec BP 550w $65 fine for crossfire with those GPUs
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

HD - WD 500GB SATA SE16 $57 (or 640 GB caviar black for an extra $20)
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

burner - $26 SATA LG (may have to disable their adware)
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Right around $600 with shipping to me, not counting rebates (if/when you ever get them)

Antec Three Hundred Black Steel ATX Mid Tower Computer Case - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Western Digital Caviar Black WD6401AALS 640GB 7200 RPM 32MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive - OEM
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

http://www.newegg.com/Product/ComboDealDetails.aspx?Ite... $119.94 (Case + HD combo)

GIGABYTE GA-MA770-UD3 AM2+/AM2 AMD 770 ATX AMD Motherboard - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

AMD Phenom II X4 940 Deneb 3.0GHz 4 x 512KB L2 Cache 6MB L3 Cache Socket AM2+ 125W Quad-Core Black Edition Processor - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

http://www.newegg.com/Product/ComboDealDetails.aspx?Ite... $234.98 - $10.00 MIR (CPU + motherboard combo)

G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) Dual Channel Kit Desktop Memory Model F2-8500CL5D-4GBPK - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $54.99

OCZ ModXStream Pro OCZ600MXSP 600W ATX12V V2.2 / EPS12V SLI Certified CrossFire Ready 80 PLUS Certified Modular Active PFC Power Supply
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $79.99 - $20.00 MIR

SAPPHIRE Vapor-X Radeon HD 4870 1GB 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $169.99 - $10.00 MIR

LG GH22NS40 22X SATA DVD Burner Black Drive Bulk
http://www.zipzoomfly.com/jsp/ProductDetail.jsp?Product... $31.99

Total - $691.88 - $40.00 MIR's

^ solid build. Both shortstuff and I went AMD for the processor, at your budget it's the best bang/buck. Shortstuff went with a superior graphic card with a single socket AM2+ motherboard and a faster processor. This should give you a basic plan to put your build together. For an operating system go with either Vista Home Premium 64 bit or download Windows7 RC 64 bit.

Shortstuff, should i go with your recommendation on the Sapphire brand video card or go with XFX? XFX has a better warranty? Thanks guys, appreciate it.

Either card would work great. I like the coolers on the Sapphire cards better, but the double lifetime warranty is hard to pass up. Flip a coin.  

last question about video card, this is a huge card, don't recommend any of the geforce cards compared to this one? I hear this 4870 takes up alot of space.

The 4870 is actually 1" smaller than comparable Nvidia cards (9.5" vs 10.5"). I would stick with the 4870 1GB card. It offers amazing price/performance due to the recent price drops.