Antec Solution SLK3800B Black Case w/ 400W PSU---------------------------------$100.98
http://www.newegg.com/Product/Product.asp?Item=N82E16811129163
LG Black DVD burner---------------------------------------------------------------------$31.63
http://www.newegg.com/Product/Product.asp?Item=N82E16827136103
Western Digital Caviar SE WD1600JS 160GB HD--------------------------------------$58.93
http://www.newegg.com/Product/Product.asp?Item=N82E16822144415
AMD Athlon 64 X2 3600+ Socket AM2--------------------------------------------------$89.00
http://www.newegg.com/Product/Product.asp?Item=N82E16819103760
CORSAIR XMS2 2GB (2 x 1024MB) 240-Pin DDR2 SDRAM DDR2 800-------------$195.00
http://www.newegg.com/Product/Product.asp?Item=N82E16820145590
ASUS M2N-E Socket AM2 NVIDIA nForce 570 Ultra-----------------------------------$99.40
http://www.newegg.com/Product/Product.asp?Item=N82E16813131022
EVGA 320-P2-N811-AR GeForce 8800GTS 320MB------------------------------------$286.12
http://www.newegg.com/Product/Product.asp?Item=N82E16814130082
TOTAL------------------------------------------------------------------------------------$861.06
All prices Newegg, include shipping, and do not take rebates into account. There is a $20 rebate on the video card and a $40 on the RAM. I think it would be almost impossible to build a $700 rig with an 8800GTS 320MB worthy of the card unless you overclocked the hell out of a cheap cpu.
You could also go with this case instead, which has a higher power (Seasonic OEM supposedly):
Antec NSK6500 with 430W PSU-------------------------------------------------------$117.98
http://www.newegg.com/Product/Product.asp?Item=N82E16811129015
...although it blows your $800 budget by almost $20 even after mail in rebates...
Of course, if $700 is your hard limit (it's not quite clear from your subject and first post), then I would suggest an X1950Pro, which would be a much better card than a 7600GT.
SAPPHIRE 100176L Radeon X1950PRO 256MB 256-bit GDDR3--------------------$171.63
http://www.newegg.com/Product/Product.asp?Item=N82E16814102061
(again, not including $20 rebate)
edit:
...I should also make the qualifier that the build I put together mainly focuses on gaming and your desire for a dual core chip. If you're not a gamer, get a lesser video card and get a faster cpu. If you go with a considerably cheaper video card, then I would also suggest that you go with a Core 2 Duo E4300 and one of the Gigabyte P965 chipset based motherboards, instead of the AMD setup (both use the same RAM).
Intel Core 2 Duo E4300 Allendale 1.8GHz-------------------------------------------$169.00
http://www.newegg.com/Product/Product.asp?Item=N82E16819115013
GIGABYTE GA-965P-S3 LGA 775 Intel P965 Express ATX Intel Motherboard----$111.12
http://www.newegg.com/Product/Product.asp?Item=N82E16813128017
Regrettably, for $800, I simply can't put together a decent E4300 and 8800GTS rig.