If he doesn't want to overclock, and it's going to be a gaming and regular PC duty rig then here is what I would go with. This is overkill for gaming, BUT will last for quite a while and will take care of other tasks if he decides to do more than game in the future.
CPU: Intel Core i5-4690
MOBO: Asus Z97-PRO
RAM: Corsair Vengeance Pro 2x4GB Kit Gold
Case: Phanteks Enthoo Pro *
PSU: SeaSonic X650 Gold
GPU: EVGA GeForce GTX 770 4GB SC **
SSD: Samsung 850 Pro 128GB ***
HDD: Seagate Barracuda 1TB 7200 RPM HDD ****
There are a few notes I should make about these parts.
* The case is just a suggestion. I have looked this particular case over and for the price, you'll have a damned hard time finding something similar for anywhere close to that money. Also, a case is personal and subjective, your friend may hate everything about that particular case. Find something from Phanteks, NZXT, Corsair, Fractal Design, or Coolermaster and he'll be fine.
** The GPU I have listed is a 4GB model. This card will run ANY game @ 1080p on the highest settings, and will run any game @ 2560x1440 with high settings at least. If he is only running 1080p resolutions, you can knock that back to the 2GB model of that card and save around $50.
*** The SSD I picked is a 128GB model. If he intends on installing the OS, programs, and a handful of games on there, he should be fine, but if he has a large game library, either buy a bigger SSD, or install the games to the regular HDD
**** The 1TB hard drive was just a placeholder. I don't know how much storage he needs, but price-wise, get at least a 1TB hard drive. He may need more, who knows........I currently have 22TB of storage in my PC, and there are others who need more than that. 1TB is as low as I would go, but for a few more dollars you can double that and get a 2TB.
This will be about $1200 and will be a solid computer for several years. I didn't add monitor, keyboard and mouse because most people reuse what they have, but if he needs suggestions for those components, I can do that as well.