First off, thanks for all the great info on this forum. I finally got my setup working based on some of the great examples and ideas.

Setup: One PC with 2 monitors (1920x1200 and 1280x1024)
C2D 3.4GHz, 4GB, 8800GTX 621/1000
Logitech G15 kb (with actual 18 G keys haha)
Vista64 (and XP) with Autohotkey loaded.

Performance with every Video options maxed (no AA tho):
25+fps (in Shattrach by the laggy fp facing the NPCs) to
100+ fps (in outdoors or UC or Org haha) on both displays.
It swings wildly depending on the number of toons and movement. I'd said 30-50fps 90% of the time. Expecting a Q6600 this week, so I am hoping it can do even better.

The surprising part is that Vista64 performs about 2X of XP - not only in fps but also the response feel. I noticed that under Vista both the CPU cores are near 100% always. There isn't any noticeable difference in response though between empty and crowded areas. It's instant!
XP's dualview performance in split head mode has to be crippled beyond belief.

I will post more details on how I setup my G keys with ahk later today. Too damn tired now.