Punta della Dogana, the triangular point which begins (or ends) the region of Dorsoduro is a fantastic viewpoint. From the end of this quayside it is possible to obtain an almost 360 degree view of Venice, beginning by looking up the Grand Canal, past the grandeur of Salute, turning clockwise to take in Accademia, much of San Marco, the campanile of Piazza San Marco, the Palazzo Ducale and in the distance the Biennale gardens. Along the distant horizon lies Lido, then closer is San Giorgio Maggiore with it’s own impressive bell tower, before you swing round to look up the Giudecca Canal. It was the ideal spot to locate Customs & Excise, which is what the building was originally.
With a camera on a tripod, you could photograph all of this and stitch them together in Photoshop to provide a grand, if very narrow, view of so much of the city.
I did have a tripod, but preferred to shoot a long exposure along the fondamenta, allowing the bobbing gondole to betray their motion by blurring slightly whilst the buildings around them remain steadfast.