Hi. I'm an IT
Professional (we are all more or less

)
In my
Professional line of work I often find myself between needing on the go portability for meetings and accessing critical data but can tether back to my desk and connect to dual monitor for serious business.
I have a 15" MBP but my 12" G4 serves this well. Perfect footprint, great performance...
If I can recall the max reso of each machine:
1920 by 1200 - macbook (latest rev)
2048 x 1536 - G4 (last rev)
2560 by 1600 pixels (latest rev)
Yes, the puny graphics capability of the train-wreck that is the 5200 graphics processor of four years ago can drive a
larger monitor in a
smaller package than the macbook, which, for this reason, won't serve my needs.
This is why I would purchase a 12"/13" inch Macbook Pro.