If you are interested in Reporting Services, you probably already know about these blogs … because frankly they have more interesting things to say than me!  At any rate, just in case they happened to slip through the cracks for you, I thought I would point you towards their blogs:

Robert Bruckner – Robert is a developer that works on the Report Processing engine and basically knows just about everything there is to know about RS.  If you have been to any of the trade shows or other various RS conferences, you probably have met him.  If you have spend time on RS forums or newsgroups, you probably read some insightful response he had to a question.  He has a great ‘advanced’ RS blog that covers a broad range of topics. 

Brian Hartman – Brian developed the Report Viewer control and has been hanging out on the MSDN forums answering your questions for years.  So if you are integrated Reporting Services with your application, you probably have used his stuff.  He’s finally succumbed to the pressure of starting his own blog to answer a lot of the common questions and themes he sees related to the Report Viewer.