I'm using a Samsung SyncMaster 305T, which is a 30.5" widescreen monitor.
2560x1600 resolution.

With IS Boxer, I have four smaller regions along the bottom of the screen.
And one larger region across the top.
Each of the regions is rendered at 1650x1080.

The slaves are large enough to know if follow has broken.
Or if they are IWT'ing off of a cliff, etc.
And with Jamba text forwarding, that's good enough.
Plus instant swap, if I need to be on another screen (usually for ground-spawn collection quests).