well, single-monitor compliance is CAKE...multi-monitor though, yeah, is a little more complicated. that's why most themers who are going for multi-monitor compliance don't take into consideration right monitor as main systems.

well, at work I use it because it's much easier (as well as more productive and more organized) to have the extra screen space. at home, because I have a game up on one screen, and a web browser, or chat windows, or whatever, open on the second screen.