While sightseeing on foot is probably the best way to get to know any city, sightseeing from the water is a pretty good second.
On a kayak tour of Melbourne, you get to investigate parts of the city that are impossible to reach by any other means.
This view of the Bolte Bridge is a favourite of mine. I only wish I had used a better camera, but decided my waterproof Olympus was a safer bet than my fancy SLR, just in case I ended up in the Yarra instead of on it!
Have you ever been sightseeing from the water?