Well, you certainly chosen the most top notch brand you can get so you're off to a very good start.
Of your 2 choices, the SeaSonic M12II SS-430GM 430W will suffice for your system.
But, I'll see your Seasonic and raise you a Corsair (only technically as Seasonic also builds the Corsair PSU's).
Corsair CMPSU-450VX 450W - $49.99 after rebate ($64.99 before rebate)http://www.newegg.com/Product/Product.aspx?Item=N82E16817139003
Lol, Sonic Boom beat me to it.