Dell ratchets up its Precision Workstations a couple of notches by adding dual core Xeon processors to the mix. The leader of the pack is the Dell Precision Workstation 690, which can be stoked with a pair of dual core Intel Xeon 5080 processors at 3.73GHz and your choice of 32-bit or 64-bit Windows XP. Add to that a 512MB NVIDIA Quadro FX 4500 graphics card that can pump out dual monitor DVI goodness, and you're loaded for bear.
Even the slightly cheaper 490 is no slouch, where you can configure it in a similar way and even use its smaller case horizontally or vertically. Fully tricked out with the fastest processors, four gigs of RAM and a couple of 10,000RPM disks, the 690 will run you about $6,500, but pricing starts at $1529. These monsters will start shipping in the middle of June.
Precision Workstation Product Page [Dell]