There's a nice (but short, and not as funny as the stuff at Cracked) story at DesignCrave about the 10 Most Stunning Art Thefts In World History. Now I can see why someone might want, say, the original The Scream on their walls... but mental Dutch dude Hans Memling's Last Judgment is just scary.
Those polyptychs (like cupboards, just without the packing space, and with over-the-top religious stuff painted on every panel) give me the heebs.