A couple of years ago I inquired about software utilities to rotate a monitor's display so that a widescreen monitor could view a large score in portrait mode. (http://www.northernsounds.com/forum/...ad.php?t=51666 - forgive my misused apostrophe).
I recently redesigned my studio (consolidated really, needed to make space now that the new baby is here) and bought a 22" widescreen flat monitor along with a wall-mount that rotates 360 degrees.
I can work in SONAR in landscape mode, with plenty of screen real estate, and then switch over to Sibelius or Finale, rotate the monitor and display 90 degrees, and work on the score. The screen is about 12x18 inches, so I can comfortably view an 11x17 orchestra score at full size, with the entire page on screen at once.
It's only been an hour but I can tell this will seriously improve my workflow.
I am using iRotate to do the screen rotation, and this mount from Ergomart (I don't mean to endorse one particular company, it's just that it was difficult to find -- every company seems to have a different definition of "tilt," "swivel," "rotate," "swing," "pivot," etc. and very few actually rotate a full 90 degrees or more).