Symlinking is the best thing to come out of Vista, imo

1 Velociraptor 300gb
4 GB ram (DDR2 or 3, or 8gb depending on budget)
2 video cards not in SLI/Crossfire, 8800GTS or GTX 260/280 (depending on budget)
Q9450 - is a good processor to look at
and of course a mobo that can handle it all. I like the Gigabyte X38/X48 boards.