The penny, at 1 cent, is virtually worthless. They cost almost 2 cents to produce, and plenty of countries including New Zealand, Australia, Finland, the Netherlands, and even Canada have already killed the one-cent coins of our economy. All of these countries simply round to the nearest five cents now and they have suffered no ill economic effects because of this. The US even killed its half cent coin back when it was WORTH MORE THAN A DIME IS TODAY. Spending pennies is simply not worth the time one needs to put in to using them.
Here are a few videos outlining good reasons to say goodbye:
"Death to Pennies" by CGP Grey:
http://www.youtube.com/watch?v=y5UT04p5f7U
"I HATE PENNIES!!!! (Also Nickels.)" by John Green:
http://www.youtube.com/watch?v=77C47XYm_3c