If it's a gaming PC, just set your budget then get the fastest gfx card you can, at least 16GB of RAM, and the fastest CPU you can. Everything else is secondary. Get an ugly case, get a 5400rpm hard disk, just don't compromise on the core stuff. Oh, and get the best controller you can, be that m&k or proper joypad, as that's what you'll be interacting with.
There you go, done. No credentials, but it's the right approach