Id recommend:
-An Intel Quad Core Processor
-4GB RAM, Maybe 8GB
-Mobo,We can figure out which one once you decide on a processor
-SSD for OS/Games,HDD for storage
-850 Watt Power Supply
-Windows 7 (Legit or not, your choice)
-Case, its up to your taste
-Graphics Card, I recommend ATI ,but I have heard good things about NVidia
I recommend you spend a good amount on your Graphics card if this is for gaming
^Thats really a rough take on waht I recommend.
The more I learn about your needs, the more specific I can be
I recommend an SSD as your games/OS/Programs will start up WAY Faster! I mean WAY!
Then maybe a 1TB HDD for storage.
How many games will be installed?