which Ram for a PHENOM II X4 955

Just bought a new mobo & cpu finally and now i'm looking to buy some DDR3 ram, i'm not sure of which brand or freq i should get though

the cpu:
PHENOM II X4 955 BLACK EDITION (3.2 GHz)
http://en.wikipedia.org/wiki/List_of...icroprocessors

the mobo:
ASROCK 970 PRO3 - Chipset AMD 970
http://www.asrock.com/mb/AMD/970%20P...Specifications

Thanks for your help