Should I go with the quad core, or i7 processor?

By the sounds of it you should be completely happy with quad core. i7 is very expensive and with that extra money you can add more ram or buy blue-ray movies. Even quad-cores and not fully taken advantage of nowadays so that means in the future you will still be set with the quad core. The i7 is mainly for high-end gaming pc's. The quad core is for heavy gaming and will 100% satisfy your needs.