The parts chosen already are top notch. Its nice to see a new builder who doesn't try to cheap out on the PSU.
as for ram, something like this would do you: http://www.newegg.com/Product/Product.aspx?Item=N82E16820226191
motherboard really comes down to the features you want. but a decent gigabyte or asus board on the z68 chipset that fits your budget will do very well.