An i5 is better, I'm going to go ahead and say it even though you didn't ask because it's only a matter of time before people show up and start telling you you're stupid for getting either of them, and that you need an i5.
You don't NEED an i5, is it better? Hell yeah, but even an i3 or FX 4300 is good enough for 1080p gaming at the moment. The FX 6300 is really good and the FX 8320/8350 is even better. The AMD's are GREAT for the price.