Jay Shendure and Erez Lieberman Aiden have a recent review in Nature Biotechnology that provides some recent data on the falling cost and increased use of genome sequencing
What is more interesting about the article is that the authors concentrate on the possible strengths of different sequencing platforms for different biological projects. They point out that the cheapest technology may not be the best for many purposes, and each application has different unique requirements.
They illustrate this with a "subway map" view, which illustrates the routes that different molecular techniques have followed, from one application to another, until they have come to be used for sequencing (the function at the "terminal").
From their later text:
The subway map analogy suggests that the development of new applications is likely to be best supported by a broad knowledge of existing and emerging sequencing protocols as well as a willingness to delve into the past 50 years of methods development in biochemistry and molecular biology. These sources effectively provide a toolbox that can be drawn on when evaluating potential routes to support new applications.
Of course, the next advances in sequencing methodology are probably already being developed by labs looking through these methods.