The general recommendation on this forum would be the FX-6300, it's a very good value and a very good gaming CPU which is overclockable with a decent board (like an Asus M5A97 R2.0 for instance), it should have no problems with most games out there
For MMOs like WoW etc. which rely heavily on powerful single threaded (core) performance, the i3 would be the better choice, however it has a locked multiplier so it has limited overclockability
Most games are entirely reliant on the GPU anyway, just make sure that you pair a decent GPU with it and you should be good for a while