Loved Pompeii, we set out from Sorrento early in the AM and went up Vesuvius to get the big picture, spent the afternoon roaming through Pompeii.
We took a day trip by boat out to Capri, view from the top (take the chair lift) is amazing. Opinions on the blue grotto are going to vary - we thought it was neat, but the experience is a touch hokey and spendy at the same time.
Stayed at Magi House, staff was first rate (arranged several of our excursions) and very welcoming.