My CPU's a Q6600 too. They have a 1066MHz bus so can't take advantage of DDR2 memory faster than PC2-4300 (aka PC2-533 to confuse us) so don't waste money. If you get one of the newer models with the 1333MHz bus then get PC2-5300 or PC2-5400 (depending on how you round the numbers) aka PC2-667 memory.

In the same vein, any SATA hard drive will do. They're all very fast. Spend the money on two normal drives rather than one Raptor. (I actually bought a Raptor for my Linux system, I don't see the difference.)

I'll second silverblade33's advice on the chipset. Nvidia make very good video cards - I have an 8800GTX - but Intel not surprisingly is the king of the Intel chipsets.

I have Vue 6 Infinite installed on two machines - I only use one at a time - because SkinVue only runs on a 32 bit Vue. I've had enough problems with what I think are simple scenes running out of memory on the 32 bit machine that I much prefer the 64 bit version. And I don't render on the 32 bit machine.