+1 @Gkay. If you get an OCZ PSU, make sure it is one of the newer models that is 80+ certified; some of their older ones aren't. Personally, I'm an Antec fanboy, but Corsair, PC Power & Cooling, Seasonic, and Enermax make good PSUs also; and the new OCZ.
Choose DDR2-800 RAM that will operate at its advertised timings on the JEDEC standard 1.8V. Anything else is a factory overclock which will actually perform worse by default. I have used this Mushkin in several builds: http://www.newegg.com/Product/Product.aspx?Item=N82E16820146731
This OCZ is cheaper, but I haven't used it myself: http://www.newegg.com/Product/Product.aspx?Item=N82E16820227465