Here's something you might consider.
Raidmax case - $69 +free shipping
AMD Phenom II Quad core - $99
Gigabyte Mobo - $105
8GB RAM - $42
Antec Power Supply - $70
Dell 20" monitor - $99
Samsung DVD Burner - $18
CPU fan - $45
Win7 Pro 64 - $140
OEM is cheaper than retail and has the exact same features. The only thing you miss out on is the "privilege" of calling Microsoft for $29 per call.
Grand total : $687
You still need a video card, mouse and keyboard.
Mouse and keyboard are cheap(can always upgrade later). Graphics card is your decision, depending on what you want to spend.
Some of these items can be switched for cheaper alternatives to save money. You could also buy some of them off eBay, like the monitor. Also, going with Win 7 Home Premium 64 bit will save you $$40. Since this is a home machine, you're probably not joining a domain, so why win 7 pro? Home premium will do everything you need it to.