I put in one of the Matrox triple head cards last year as an upgrade from the double. It works great with all the Sony products. I often have Acid up on the left and Vegas in the middle with Sound Forge on the right for editing. Great to have all that real estate. But even when I just use Vegas, I pull screens all over the place.
Do you know that the new Vegas 5 can memorize different desktop settings and you can switch between them?