I have a Q8300 in my primary system and a G3258 in my secondary system. Both systems use the same graphics card. I can recommend the Pentium for general gaming and use, as it's a much faster chip in general. However, in thread heavy games like FC4 and BF3/4, I see less FPS drops and stuttering with the Q8300.
It's down to personal preference. I would personally go with the Pentium as it allows much better future upgradability.
Woody