The only reason I'd get a notebook with OS X over Win7 is because of Spaces. Just makes working on a single screen so much easier I feel.
And RainMeter uses considerably less RAM than the Win7 gadgets do. It is a bit awkward to get full balance on my desktop, as far as icons and such go, because the left display is usually an app window at full screen, while the right display is almost always music, chat windows, and what not. As a result, I tend to place widgets over on the right screen, just because I can see them all.