So, I shortened it. See:
http://bit.ly/i8zRxz

Did I miss something?

We all know what a second monitor means to the developer-at-large. We all know as well that a second monitor is most often not a need, but a desire.

What we may not be considering is the type of developer the question is posited for, and what that developer's optimal screen real-estate needs are.

If you are involved in the purchasing of computer hardware for your developers and are looking to get a jump on what a new developer on your team might need, I humbly submit the following guidelines:

The Mac developer needs two monitors. One monitor to run XCode, Mono and Eclipse (all at the same time) - the other to run the iPhone simulator to full effect (the iPad, just being a really big iPhone anyway).

The Linux developer needs, at a bare minimum, two monitors. One to run EMACS, the other to run Firefox (or alternately Opera) pointing to http://slashdot.org./ Possibly a third if sourcing to Subversion.

The Windows developer needs only one monitor. It will be used in full displaying IE9 pointed at Facebook, Fox news, some cute "LOL cats" website with flashing "you are the 1 millionth visitor" and some pr0n tabbed out and ready for fast switching. It doesn't have to be really big either as none of the site form-factors are really above 1024x768 pixels.

I hope this helps.