Especially at the moment, through these turbulent times for the global economy, I'd say the most compelling read is Robert Peston's BBC Blog.

You have to hand it to the guy, he has stamina, the blog is updated frequently and when he has a story to break, he breaks it on his blog. The tone is informal and accessible in a way that is pehaps surprising considering he is an employee of The Corporation. It feels authentic and you really feel like Peston has a real belief in the medium he is writing for.

Almost everytime I visit I learn something I didn't know before. To that end, if you were to ask me for an archetypal good blog, I'd urge you to read his.

(There a few more business/finance blogs I've just recommended here...)