Here is the complete list of manufacturer recommended power requirements for systems with pretty much every graphics card configurations you can think of. http://www.realhardtechx.com/index_archivos/Page362.htm
Remember this is for the whole system and the list assumes a "generic" power supply. If you get a high quality power supply you are generally fine with a bit less than the list says. High quality brands include Corsair, Seasonic, PC Power and Cooling, XFX, Silverstone, Enermax, OCZ and Antec.