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The EVGA x58 SLI-3 is an excellent motherboard! Performance-wise you do not need to upgrade this board, but if you want more 'bells and whistles' then you can go to a EVGA Classified motherboard.
Use the X-58 SLI for a few weeks, and then decide.
I have the EVGA Classified and I am running my i7-920 at 3.82 GHz OC. Very stable and excellent temps using a CM V8 heatsink.