I want a new workstation with some super duper hardware. I'm planning for this to be a purpose-built video editing station, and I don't know quite where to start!
What should I look for when building in this system?
Video editing is one of those rare cases where a multi-core machine really makes sense. You want a machine with 4 or even one of the new six-core i7s, and lots of RAM. If you've got money to spend and are doing some really serious video editing I might even go dual-Xeon (6 cores * 2 cpus * 2 for hyperthreading = 24 logical processors).
A fast hard drive doesn't hurt either, though I think I might prefer 2 WD Raptors in RAID-0 over an SSD in this case.
Finally, some editing software supports off-loading some of the processing to video cards. Typically, when software supports this it will only support it for cards from either nVidia or ATi, but not both. You should check your software and make sure to choose a supported video card to be able to take advantage of this feature.