Here is a nice example (http://www.ericson.net/content/2009/10/how-big-is-that-phone/) of how to scale an object of interest (a mobile phone) by showing it next to other well known objects; an iPod, a pack of playing cards and a pad of Post-It notes.
This also acts as a link to the blog of Matthew Ericson (http://www.ericson.net/content/) the the deputy graphics director at The New York Times, where he manages a department of journalists, artists and programmers who produce the interactive information graphics for nytimes.com, as well as all the graphics for the print newspaper.
He has some nice maps and interactives graphics - his multi-decade analysis of the #1's of Michael Jackson is also interesting (http://www.ericson.net/content/2009/06/the-king-of-pop/)