The fare varies, but in all major cities, even Nanjing, Hangzhou and Suzhou, the taxi-drivers tend to overcharge. It is important to negotiate the price before getting into a cab. In Hangzhou, beware of drivers who take you on a complete drive round the lake even if you are just trying to get to a place couple of blocks away. Nanjing is a great place to experience cycling in a big city. Hence, it is quite safe to go biking in Nanjing.
Cycling is also a good option when taking in the sights round the lake in Hangzhou.
Surprisingly, bike rental is not popular there. You can try your luck in one of the major hotels. Suzhou with its narrow streets is not so kind to cyclists. It is much safer to take the bus. The streets in Shanghai are far too crowded and cycling can be suicidal.