I think you'll be happier with an i5 as the 8320 will bottleneck in some instances. In some games, the i3 outperforms or performs on par with the fx 8350. I believe Shadow of Mordor is one of them and I know Planetside 2 is very CPU-intensive.
However, the i5 will run you a little more than the fx 8320 so if that's your budget, I think you allocated the funds appropriately.