Need Advice On Building A Gaming Tower

I am seeking to build a computer within the budget of $700-$750 If Cheaper BY ALL MEANS.

I am looking to run these requirements:
Windows® XP/Vista/7 (latest service packs) with DX 9.0c
Intel Pentium® D 2.8 GHz or AMD Athlon™ 64 X2 4400+
NVIDIA® GeForce® 7800 GT or ATI Radeon™ X1950 Pro or better
1 GB RAM (XP), 1.5 GB (Vista/7)
12 GB available HD space
DVD-ROM (required for retail disc versions only)
Broadband* Internet connection
1024x748 mini

These are the requirements for Diablo 3. Id like to be able to run them smoothly if possible.

I need all of these: (Case) (Power Supply) (Motherboard) (CPU) (Memory) (Video Card) (Storage) (Optical Drive)

Basically everything and if I missed anything to make a computer tower healthy and running.

Also if you could suggest your favorite Trusted and Good Priced Sites I would appreciate it. The only one I've got so far is NewEgg.

I appreciate every reply and YES I am a computer Dumby.