That depends what you want
Do note that the core works on the older 775 socket motherboards IF it has updated Voltage controllers which some companies are updating with older motherboards to support the new core.
This should proove that alot of new version motherboards should become available rather quickly,
But I'm sure if you look carefully, you'll find a nice selection.
Where abouts fo you live?
Are you looking for SLI or CrossFire or just a standard 16x PCI-E slot?