I play with two monitors.

My left monitor, is the active region in the full monitor (27" widescreen, 720x1080).
My right monitor has the other regions, displayed in roughly the top left quarter... which makes them rather small, but I can visually check if they're following or what not... and with instant swap between regions, that's good enough.

I also run Xsplit broadcaster, iTunes, Firefox and often a DvD on the right monitor.