This will be my first build I have made myself. THe main things I am concerned with are the GPU and RAM. From what I have heard Sapphire is a good brand but I haven't had any first hand experience. I have only heard good things about Corsair so I am assuming the ram is good.
Check the Asus or Cooler Master forums to make sure that 212+ can clear those heat sinks on that RAM. but ya, that h/s will do fine for that o/c. Also that build with two of those cards might top out at 525w tops...and thats figuring in o/c on the cards and the cpu. 750w is way more than enough. Otherwise that build looks solid.