When I traveled to Rome and Palermo it was by cruise ship. We hired a private driver for Rome and I think I could have easily spent a whole week there. We saw a lot in 8 hours but we only touched the surface. I would love to go back and spend more time. It is beautiful and so much history. I was in awe.
World's best Neopolitan pizza and sfogliatella and a good jumping off point for Capri or Pompei but be careful if you intend to spend any time in Naples at night. I was mugged twice in a period of 10 minutes while there a few years ago.