I'd have thought a Mac if its graphic design...
I hear any designer who doesn't use a Mac gets laughed right out of the whole scene..
Anyway, as outlander said, I7 reigns supreme, 64 bit windows with 64 bit applications are the gold standard to go for. If its more CAD/CAM you're into then Labview and AutoCAD programs are multi-threaded, making good use of the quad core I7.
If you favour speed over storage then go for SSD's, if you need tons of storage then there are plenty of sub £100 (even sub £50) 1TB storage disks on the market today that will do the trick.
6GB of DDR3 RAM is going to suffice but if you are seriously multitasking then go for 12GB.
As for video, Nvidia and ATI both have design specialised cards on the market that are apparently optimised for this sort of stuff (Quadro and Fire respectively). But a GTX 285 will be a good choice since the CUDA technology inside it is second to none. Then again i don't know how the new ATI 5 series cards are performing so maybe consider one of those.
But if you're newly trained in this profession, shouldn't you kinda already know? :S