As above, Pompeii and Capri and also take a trip up Vesuvius. Sorrento is fantastic, anyway but a trip down the Amalfi coast is also recommended. Beautiful part of the world. The pizza, pasta and gelato are, as you might expect, superb. You should also try to see the fishermen bringing in their catch in the bay. Be careful going deep in to Naples itself as it gets a bit sketchy away from the bay; think Keighley by the sea.