Stephen O'Grady, analyst and co-founder of RedMonk, is a guy who clearly understands both the existing IT industry and the impact of open source. I've had the pleasure of getting to know Stephen over a few years and while I have not always agreed with all of his analysis, I always respect that he has done his homework to understand the real issues. While many of the larger analyst firms in the industry have a reputation for staying at the 50,000 foot level, RedMonk dives down to a much deeper level.
Stephen's blog, tecosystems, is a good place to get familiar with Stephen's thinking. He's recently written about the changing landscape in the database industry as a result of open source technology. His analysis is smart and to the point. Here's a few recent postings that are thought provoking.