this is the best priced board that would suit all your needs, it has 4x USB3.0 and 2x USB 2.0 and has support for SLI, from ASUS:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813132287&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-PCPartPicker,%20LLC-_-na-_-na-_-na&cm_sp=&AID=10446076&PID=3938566&SID=
This is simlar price and feature but different color scheme:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813130801&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-PCPartPicker,%20LLC-_-na-_-na-_-na&cm_sp=&AID=10446076&PID=3938566&SID=
