The Pompeii ruins are one of the most tourist-visited sites in the world, which is one reason to stay home, sit on your couch with no pants on and enjoy the ruins on Street View. It's pretty gorgeous. [Google]
Pompeii was so blah, it was the imagination tour. This pile of rocks was a noble house, this pile of rocks was the bath. The only cool parts were the people who were trapped in the lava (though really eerie) and the one building that survived, which happened to be the whorehouse. I would have rather spent an extra day in just about any of the other cities I visited in Italy.