Venice is beautiful. Do not leave without visiting: Basilica di San Marco, Piazza di San Marco, Burano and Palazzo Ducale.
Insider Tip:Book ahead in plenty of time if you want to take the Itinerari Segreti tour in Palazzo Ducale and if you want to go up the Torre dell'Orologio. Otherwise you will be disappointed as I was. Make sure you visit Piazza di San Marco at night and go to Gran Caffe Chioggia - the live classical music is so beautiful it will bring a tear to your eye. Buy a two day pass for the valporetto and learn how to use it to travel in Venice. The crowds of people in the streets are horrific everywhere all the time.