Canon and Nikon are very close to losing a lot of the pro market. Companies like Sony, Olympus, and Pentax are offering a lot more - more features, performance, and technology, not just more for the money - in their "pro-am" cameras. This is where the digital market could have been 5 years ago if Canon and Nikon hadn't used their market position to actively manipulate the industry.
http://www.dpreview.com/reviews/pentaxk10d/