Minimum I would recommend is an Asus M5A97 R2.0 (not the LE version). But if you can afford a little more, the Asus M5A99X EVO R2.0 is better, especially if you plan to overclock.
Sometimes, the Asus M5A99FX PRO R2.0 costs the same as the EVO. So if that's the case, get the PRO instead.