The U.S. should cease production of the penny.
As of February 2012, it costs about 2.4 cents to mint a penny meaning that the U.S. Mint loses $100 million each year minting new pennies (http://cnnmon.ie/yE473n).
Pennies have limited utility due to their low value and the fact that they are not accepted by most vending machines and toll booths.
Further, it is estimated that dealing with pennies adds 2-2.5 seconds to each transaction. Eliminating the penny could save Americans a total of $1 billion each year (http://bit.ly/yVVuuQ).