well.. looks like you picked a CPU. the HD's shouldnt be a problem, since about all motherboards wupport raid 0.
now look weither you want to get a crossfire/SLI motherboard, or that just 1 (pci-e) grafic's card is enough. if you have deciuded on that, chose a motherboard, and after that you chose the RAM that fit's it ( like dark said, that would be ddr2 ram)
then you look for a nice PSU ( mainly dependant on the grafic's card you get, but if you have a good branded 500W PSU, you'll be fine anyway
)
and ofcourse a nice case where everything fit's in
