The Periodic Table of Periodic Tables
Also available on Flickr make sure to read the caption if you're a chemist, self-righteous datageek, or curmudgeon.
Sorry for the lame interface here. It's not easy to display large things on the Web.
Click anywhere to zoom/drag and click the arrow icons to go to that periodic table (link will pop in a new window).
Sources: Internet Database of Periodic Tables, jonesthought, Google, Wikipedia, curiosity, restlessness, etc.
See also: 50 Sad Chairs | MILK EGGS VODKA: Grocery Lists Lost and Found based on grocerylists.org | I am keaggy.com.