It pains me that you have to go with an Nvidia board, but the 8800GT in SLI is the best performance you're going to get for $300.
Is this solely for gaming? If so, then yes, it would be a better choice to go with a higher clocked dual, the E3110 being the pick of the bunch:
http://www.newegg.com/Product/Product.aspx?Item=N82E16819117165&Tpk=E3110
Of course, you could wait a few days and get dual HD 4850s and a P35, X38 or 790FX board. But two if those cards would be more like $400 rather than the $300 for GT SLI.