Why should you increase beyond one monitor?

Why should you increase beyond one monitor?
That picture is a 19" wide screen monitor. What I held up over it was an 8.5x11 sheet of paper. It's obvious, (isn't it), to think you can manage complex amounts of data through a square portal barely larger than a sheet of paper successfully, is just ccccrrraaazzzzy. No wonder we have a hard time interacting with computers.

Stay with me. Take out a sheet of paper and place it on your desk. Now, for the rest of the day that's the surface space you can work on. How long would it be before you got lost, distracted, overwhelmed, etc...? Help me; become an advocate for multiple monitors.

1. PARC: Wideband visual interfaces
2. 30 Inch Cinema Display [may] Boost Productivity up to 73%
3. Two Screens Are Better Than One
4. The Virtues of a Second Screen
5. Monitor becomes hot-swappable
6. Examples of massive multiple monitor displays
7. Microsoft: Expand your workspace with multiple monitors
8. Two 19" monitors will cost around 400-500 bucks. I'm saving up for three and am still thinking about the size combination.

xx. Dream on.