For Crossfire, if you can find one in stock, the Asus P5W DH looks to be a great board. Although, I think that all 975X based boards are Crossfire compatible, but not all are Conroe compatible, so check for that. For Conroe and SLI, the only game in town right now is the Asus P5N32-SLI SE Deluxe. The nForce 570 and 590 chipsets should be out somewhat soon though, so that will change.