I do work in a cube and I haven't put anything personal in it, mostly because I kind of don't see the point. But a lot of my co-workers have tons of plants and pictures and calender and knicknacks, and, well, I don't get it. It kind of seems like trying to gild pig poo, in my opinion. It's a cube, folks. All the kitschy garbage in the world isn't going to change the fact that you're stuck in a 6'x4' physical manifestation of soul-less corporate policy.
....or I could just be really, really cynical and not cut out for office work, or something. :P