the i3 is a definite in this price range.
Now a few more things before you can start a list tech. Do you need windows, or do you have a copy? Also, does your friend have the keyboard, mouse, and LCD, or does he need those too? Also is there any components that he wants to reuse?
If you don't need any of the above except for windows, I would suggest that you go with:
GTX560ti or HD7870
i3-2100
P67 motherboard from Gigabyte, AS rock or MSI in ATX form factor
8GB DDR3-1600 CAS9 or CAS8
500+ GB HDD from Western Digital, or Seagate
Quality case of your choice
PSU in the 500-650 watt range from Antec, Corsair, NZXT, PC power and cooling, OCZ, Seasonic, Silverstone, or XFX
and a DVDRW drive.