You're gonna get loads of different advice on this, so here's mine.....

Quad core processor or the new i7 if money's no object.
64 bit Windows 7 Ultimate
9000 series Nvidia graphics [9800GT is a good choice]
8 Gig RAM
3 x 500 gig HD's with 2 in Raid 1 array and 1 for storage. The spare can be used for back ups etc, no need for an external drive.
Antec gaming case with all the fans, really excellent cooling.

That's it, this set up will also do if you decided that you wanted Vue 8 as well or something else, because Vue is proper 64 bit application so you can use all that RAM up there.

Injustice will be avenged.
Cofiwch Dryweryn.