Get two hard drives (placing the swap file on a secondary disk is a huge performance boost alone), but skip the RAID array like everyon said. 1 GB of RAM is fine, but I have 2 GB and I definitely use 75% of it (I do a lot of multitasking, though). I suggest looking into a case that supports water-intercooling for your processor and video card(s) so you can easily support overclocking and have a quieter running case (no need for tons of exhaust fans).