As I promised quite a long time ago, I make a list of the Business Intelligence sites I regularly read.
I'm not always on the topics being discussed, but I learnt a lot for sure from them. I'll never thank enough those people who share their knowledge online. This is by no mean a complete or a popularity based list, and is grounded only in my personal taste.

BeyeNETWORK is the battleship of BI sites. Many of the most famous BI stars write here or their blog is hosted here or is aggregated here. Bill Inmon, Jill Dyche, Claudia Imhof and many others. Articles cover BI at 360 from high level philosophy discussion to low level implementation, from market news to change management in BI projects.
Being a rather cynical guy, the one defect I find that it is a little biased toward large, enterprise-size analysis.

TDWI is just an inch back from the previous site. It is not a totally informational site as it provides education and consulting, and it is better enjoyed with membership.

If I could, I'd marry this girl: Inside The Biz by Jill Dyche is one of the most insightful sites I have ever came across. She deals with a variety of topics, not all BI related but each and every article is worth reading.

For those who can read French, Le Grand BI is an immense enjoyment. Their prominent feature is a cynical and disillusioned approach to all the hype and buzzwords that sometimes blind us. I often refer to them to have a second opinion.

As I work for a large part in Microsoft ecosystem I use and like the Microsoft Resource Center . What's outstanding here is that you are taken by hand and brought to the highest level seamlessly by a host of written and filmed footage. Donald Farmer articles are a must read for all those who work with MS products.

Last but not least Oz-Analytics provides an always interesting point of view. Starting from other articles or real life experience, I've never read a trivial point of view from this guy.

As you can easily notice I leave out all those bloggers who deal mainly with the technical side of the job. Actually there are a lot of them worth reading, some fundamentals. This a good topic for another post, I'd say.

Enjoy.