I have been using the excellent Canon ZoomBrowser EX software for several years, as I have owned several Canon consumer products. I like the feature set and simplicity of this program.
One of my pet peeves with it however is the slide show feature. It always goes to the primary monitor, in my case the 2 megapixel monitor on the left. It never goes to the 4 megapixel monitor on the right. There is no option in the ZoomBrowser slideshow setup to choose the monitor. Even if all ZoomBrowser windows are moved to the desired monitor, the slideshow always ends up on the primary monitor.
The only workaround I have found for this is to disable the lower-res monitor in Windows 7. Then ZoomBrowser has no choice but to display the slideshow on the one and only remaining 4 megapixel monitor.