There so many flavors of the GTX260 and so many flavors of SLI Motherboards. It's really difficult to say which is best. I like MSI products but i've seen a lot of people buying EVGA.
I'm running an older SLI MB, MSI-P6N SLI FI and 2x GTX275's from BFG... So far so good....
It's really up to you as to which manufacturer you want to go with...
AJ