A macro of a graph in Edward Tufte's "The Visual Display of Quantitative Information", a classic on graphic design of data displays. This particular graph shows the weather of NYC over a year, and this particular data is the actual and average amount of precipitation in a month (not sure which one).
One of Tufte's principles is to maximize the information to ink ratio--only use ink to portray what the data needs. In this case, a two-category bar graph alone has rather poor information to ink ratio--all that ink to portray two numbers! However, this image is only about 1/50th or less of the total image, so its tininess makes it tolerable.
If you're looking for a last minute book gift, this is one of the most stunning coffee table books I have, AND it's got wonderful insight for anyone who works with data and visualization.