Sorrento is a good bas as that is where all the transportation links are, but I hated the town - far too touristy. It is a great spot to head to Pompeii, which is a must (I'd recommend reading Robert Harris' book of the same name - it is fiction based on as much fact as possible but gives you a really good idea of what the town would have been like back then). The bus around the Amalfi coast is a wonderful trip & all the towns around there are worth a visit. The Isle of Capri is nice, but again, very touristy - we took the boat to Ischia & this is far less touristy & very much a working community.
We didn't go into Naples as everyone (especially the locals) were warning us about theft & muggings - though, generally in Italy, I tend to feel very safe.