I think it is the most important blog covering constutional issues. In addition, his insights on political speech are incredible. Reading one of his blogs puts a whole new light on media personalities including those in print journalism. I am looking forward to his new book.
I agree with both of these comments -- Greenwald is brilliant and is invaluable at seeing through the spins and BS to explain what something really means or will do, he spares neither side, and being not only extremely intelligent he's also a constitutional lawyer, which means when he starts talking about who's breaking what law, you know he's not using his personal opinion as to what the law is. His blog is the first thing I read every day and I try to catch him on web talk shows and TV talk shows every time he's on. What he does is all the more remarkable after learning he's been based in Brazil for the last year or two, returning to the States for brief periods every few months. He still stays on top of everything and I think this gives him a very good POV that isn't influenced by the Washington pundits of either party. Man is truly a national treasure.