The trading workstation I use is one I built myself, from parts from newegg.com, it's rock-solid and works like a charm:

+ Asus P5WDG2 mobo
+ 4 gigs ram
+ 2 ATI Radeon X1950 dualhead pci-e cards (runs 4 widescreen monitors)
+ logitech mx518 mouse
+ e6660 dualcore intel cpu
+ miscrosoft natural keyboard pro

Tip: I've also custom-built a lot of extra flourescent light fixtures for indirect lighting around the top of all the walls, for a lot of additional lighting.

Ken