This suggestion is ONLY if you've already bought the other parts. If you have, you've done an injustice for your friend cuz s/he could have a lot more computer for the same price. The power of the C2 line is in its ability to OC, not its stock performance. Intel beat AMD until the Phenom IIs that could do both. In this price bracket, AMD still is a fav over the core i5 at stock.
D3 is built on a DX9 engine. It really won't task a mid powered GPU even at the 1920x1080 resolutions. Same with the older games like HL2 orange box stuff and L4D. The 4850 1gb can hang in there. Depending on the mobo you picked, a second one in a year will really let this rig have a good long life. But the Q8200 isn't really going to cut it at stock speeds. The cache is too low too.
This CPU is still a little slow, but you can get the Q9400 and a 4850 1gb for $290.
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.231120
OR if you can add just a few bucks,
The Q9550 for $220 and the 4850 1gb for $105 or so. No combo there.
If you won't take a lower vid card, go with the 4870 1gb and get a FAST dual core instead of the quad. The E8400 is $11 over budget or the E7600 will come in just under.