No, don't go crossfire. In about 1 year we should have the next next generation. AMD releasing new cards soon, NVIDIA has already released 700 series... by this time 2014, we could be into the NVIDIA 800 series and AMD whatever-comes-after.
In any case, your resolution isn't so demanding that 7970 would make sense. Crossfire/SLI works when you have a monitor setup that can properly use it, and you do it right away instead of planning to do it later.
Out of curiosity, what motherboard did you get?