We have done the tour thing of St Marcos basilica (so much gold glittering!), the Doges palace (including the adjacent prison via the bridge of sighs), the Grand Canal cruise (all those palaces while sipping Bellini peach sparkling wine), and the cathedral Frari Which houses Titians Madonna of the Assumption and is much more austere than St Marcos basilica. We have yet to round out the tour scenario with a gondola ride (for some reason the time got messed up yesterday afternoon) so we will do it this morning. The snazzy thing is that the gondola will pass right under our motel window! We have really enjoyed watching them swan past, especially when they have a singer, piano accordion or classical guitarist on board.
But best of all has been our self guided walking tours- I wish I had my pedometer with me so I could gloat about how many steps I am doing!