Some of the Intel 6-series motherboards have an issue with the chipset (the SandyBridge issue). I would wait until this issue has been resolved. These boards use the P67 and H67 chipsets. A fix has been developed, and should be with the motherboard manufacturers by the end of February. New/replacement motherboards should start to become available during mid April.
That issue aside, when changing a significant piece of hardware (and a motherboard is about as significant as you can get), I would strongly recommend a clean installation in order to get the best performance.