There is a lot more to the Veneto than Venice; with mountains and
lakes in the North, through some fairly bland, but productive
plains, to Venice itself via some particularly nasty industrial bits
around Mestre. You can
get a taste of just about any part of Italy's cultural wealth in the
region, Renaissance and Gothic architecture, quaint little hill
towns, medieval castles, fortified towns, art galleries the envy of
the world, food, wine...
Of course, you just have to do Venice, but you
can also have a wonderful time driving aimlessly around the
countryside, stumbling upon towns like Marostica and Asolo, which
were not really on my planned itinerary, but turned out to be quite
special in their own ways.