That's what I heard from Helene Blowers last week. She encouraged everyone who isn't currently reading blogs regularly to start with five....
LibrarianInBlack - http://librarianinblack.typepad.com/
resources and discussions for the "tech-librarians-by-default" among us...
Life Hacker - http://lifehacker.com/
tips and downloads for getting things done
LibraryStream - http://librarystream.wordpress.com/
Watching the flow of the participatory library.
Wired - http://blog.wired.com/
Learning 2.1 - http://explorediscoverplay.blogspot.com
created to support on-going discovery and learning of web 2.0 technologies as an extension of the Learning 2.0 program.
And I'll add a sixth - but since you're reading this you've already gotten it ;-)