RAM: 2GB is the ideal configuration for 64-bit Vista, we're told. Vista 32-bit will work ideally at 1GB, and minimum 512. However, since 64-bit is handling data chunks that are double the size, you'll need double the memory, hence the 2GB. Nigel mentions DDR3 - which is a little odd, since the roadmap for DDR3, on Intel gear at least, doesn't really kick in until 2007.
HDD: SATA is definitely the way forward for Vista, due, Microsoft tells us, to Native Command Queueing. NCQ allows for out of order completions - that is, if Vista needs tasks 1,2,3,4 and 5 done, it can do them in the order 2,5,3,4,1 if that's a more efficient route for the hard drive head to take over the disk. This leads to far faster completion times.