This thread here might be of some use to you, when considering the tradeoff between DPI and system resources at various sizes - http://www2.ambientdesign.com/forums...highlight=size
Regarding the monitor, I see what you're getting at. You may want to see if you can take a look at the monitor yourself and see how satisfactory the viewing angle is. These days I find LCDs are pretty good, a lot nicer than they used to be especially in terms of viewing angle. If you're happy with your current monitor though, there may not be a big advantage for you personally.