The Pentium G860 is roughly equivalent to the Phenom II X4 at stock speeds, without overclocking. It'd be a solid choice on the Intel side, but if you wanted AMD, I think they may have the upper hand sub-$100.
The Phenom II X6 Six Core is only 90 bucks at microcenter, so if you want AMD, that'd also be solid. Honestly, I'd go with the AMD 6 core over a Pentium, but that's just me.
The G680 is better for it's price, though. You'll be able to get a better graphics card.