Depends what you want mate but the Amalfi coast is my personal favourite area. Got a bit of everything. You've got the old ruins of Pompei and Herkulanium, which are really interesting to visit. do a trip up Vesuvius, do the bus trip down the coast to Positano, home of the rich and famous, beautiful little place, google it. Apparantly George Clooney has a house there. Get the boat across the Capri which is fantastic. The other way you've got Naples which is an interesting place. Sorrento is a nice town to base yourself in, lots of good bars, restaurants and shops and good and cheap public transport to all the places i mention.
We're off to the Venice area in September, not been there before.