Although faster processors and more ram are an endless pursuit, I find 2 monitors essential. I'm a graphic designer that uses Photoshop, Illustrator, InDesign and RayDream (not much Carrara now because of bug issues) all day long. It makes work so much easier when I can concentrate on only the image on one monitor, yet have access to all of the palettes and tools at one glance on the other, without having to continually open and close or move things out of the way. With 3D, I like to use the other monitor for the hierarchy or timeline windows only to allow for viewing most, if not all the elements in the scene.