Because 6 was not enough. Thanks to the HIS Multi-View II DVI to USB adapter, I was able to add another monitor, on top of the three monitors allowed by the Matrox TripleHead ToGo.
In case you are wondering, each screen has a dedicated function. My MacBook Pro screen is always trained on my gmail. The screen furthest to the left holds my Tweetdeck and Instant Messaging. The next screen to the right holds whatever document, or documents I am reading. The main screen in the middle contains whatever I am typing. The screen furthest to the right contains my Google Reader. My old Macbook Pro is used for ancillary stuff or testing things, and sometimes I will play a video or something on my Nexus 7 Tablet.
The idea is that I can quickly glance at any screen, and know exactly what I’ll find, without having to switch windows. Everything is alway open.
This is the virtual equivalent of laying out a lot of books on a big table, and being able to see many thing at once–just much more efficient. (In the proces of writing my single book, I have not used a single actual book, nor have I put a pen to a single piece of paper).
Here is my old workspace.