For a mere 300$, I think the upgrade worth it.
Remember that in a half year time, I doubt you'll get even half the price you're getting now for your current rig.
About the CPU- the i7 950 is your best choice for the money, and an upgrade to the 980X does not worth the extra 750$~..
Games benefit more from high clock speeds(which the 950 has) rather then number of cores.
And with the Gigabyte M.B. recommended by dangtx, it's a great build choice.
Remember that in a half year time, I doubt you'll get even half the price you're getting now for your current rig.
About the CPU- the i7 950 is your best choice for the money, and an upgrade to the 980X does not worth the extra 750$~..
Games benefit more from high clock speeds(which the 950 has) rather then number of cores.
And with the Gigabyte M.B. recommended by dangtx, it's a great build choice.