How much power does my computer need? Should I think about switching of my lamp when I am not in my office? How much energy does a typical Laserjet use for one page? For those who are interested in these numbers, here is a nice image compiling these informations. 
Thanks to Stefan Meinel, Katy Richardson, Rosie Robison, Amanda Stagg and Mick Young.
[These numbers are not to be taken as high-precision measurements. Especially the numbers about boiling water and printing can have a +/- 50% measurement error in them. But that is also not the point: This is to give you a rough idea of how much energy you consume in your office using everyday appliances. The specific devices you are using might be very different from these anyways.]