Mr Carlson,
Even with my dual** 27's I want more modeling area than interface area. The size of the monitor is meaningless, rgardless of its size I want the MOST modeling area possible. The LESS the interface interferes with modeling the faster/better/more efficient is the production. Ribbons are collapsed and out of the way, certain necessary palletes like properties, layers, xref, and design center are relegated to the left monitor. Right monitor is nearly all modeling area usually divided into three viewports; two small ones on the left and a large viewport for primary modeling. The interface is heavily customized keyboard entry with a very few pull-downs or pop-ups. That is most efficient FOR ME and the production capabilities I need.
** Now that AutCAD has begun to look like Microstation with a multiplicity of 'palettes', a second monitor to contain those is useful. I can be just as productive without that second monitor, but others hamstrung by the plethora of screen eating interface 'junk' need the second monitor in which to model. a grudging acquiescence