My rig is pretty old about 5 years.
But most of the parts were upgraded at that time and is still pretty relevant.
ATI 5870 2gb
I5 2.67gz processor
8g DDR ram
My old 1.5T HD was a total slug.
Bought a very basic 120GB SSD just for windows and D3 + w/e programs I use regularly.
OMFG.... what an upgrade. Run max settings with numbers, etc. No start up stutter, barely loses frames. This is all solo of course. in crypts still got lag from server.
Welcome to the 21st century as silvefire said....