The thing is, I won't be building my new PC until March or April.
From experience of those who are constantly on the look out for good GPU deals, would it be worth it to wait until I start building or jump on an awesome deal like this which has a rebates and 2 awesome free games?
I would wait, pc hardware prices fluctuate too much to buy a part before you will actually get to use it. A good example of that is the fact that the link you gave has the card for $330. I ordered the card monday for $300 with the game deal. Going to pair it with my current sapphire 7950 for crossfire.The deal will probably run for a few months at least and by the time you're ready to build the card may have had another price drop, especially if the 8*** series is on the horizon.
Prices fluctuate all the time. The price on that one rose, the price on the gigabyte dropped. No matter what, when you're ready to buy you should easily be able to find a good 7950 for the $300 base price.
The core clock really doesnt effect overclockability, unless you mean the lower the core clock the more headroom the card may have. I think the base for a stock 7950 is 800mhz. Anything above that is considered an overclocked card. Both of my cards have different core clocks, one is the OC edition with a core of 900, the other card is a boost edition with a core of 800, but boosts up when needed. As far as overclocking, both seem to be able to reach the same with no problems and I run them at 1100/1400 when I need extra power.