Apart from the library bloggers, that is ..

1.  Guy Kawasaki.  I love his writing style and nearly always learn something new.

2.  Stephen Downes.  Enjoy his tone of voice (and, of course the content.  I wish I could read as prolifically, and comment as succinctly as he does).  Actually the link is to his newsletter 

 3.  Garr Reynolds .  He always brings a new way of looking at my craft.

4.  Ali Brown.  She takes me along on her transparent, but always fun, promotion of herself and her successful business.

5.  Dave Pollard because he makes me think.