^Well, I say for price/performance. You would pay $349.99 for a mobo with less characteristics that the P6X58D.
The Rampage II Extreme looks good, but IMO is a little expensive if you compare this with the P6X58D.
Now, for the RAM, you can go with any one of this
Mushkin 1600 CL6, is the best RAM that you can get.