Like Bob I use 2 23" monitors side x side. I don't think I would want one large one unless it were 4k and even then I would have reservations as a large one would be too close in my environment.
 
I only use the 2nd monitor in some apps but it sure is handy at those times. I use the main for track view and the 2nd for the console, browser, piano roll, etc. In Vegas, pretty much the same. The track view in one and full screen preview monitor in the other.