The parts you have selected will meet the minimum system requirements for both games, however the recommended system requirements are greater for Diablo 3 and they are:
CPU=Intel Core 2 Duo 2.4GHz/ AMD Athlon 64 x2 5800+
Video=nVidia GTX 260/ ATI 4870
Thanks for replying noreaster. As soon as I had posted this I ended up changing to the Pentium G series. Microcenter has a Pentium G630 for only $49.99 right now. Sounds like a great deal.
I also found a HIS Radeon HD 6870 for $123.99 (free shipping). According to Passmark and HWCompare the 6870 appears to be a slightly better card.
Microcenter also had this motherboard for $49.99. Not sure how it compares with the one you posted. Thanks again for taking the time to help.
And one more thing: How do you feel on refurbished hard drives? I have really old IDE drives and decided to add a SATA drive. The refurbished ones are much cheaper. Didn't know if there were any major concerns using them (I've had these hard drives for nearly 10 years without any issues).
The processor, video card, and motherboard look like good deals.
All hard drives will fail at some point simply because they are mechanical in nature, that is the only reason I stay away from refurbished hard drives, you don't know how many hours of use they have and thus no idea how many hours of use are left, but that is just my opinion.