Ariadne - http://www.ariadne.ac.uk/
The UK is doing so much to push the library envelope, that keeping tabs in what they're doing is important. Ariadne is one of the most effective ways to do that.
Current Cites - http://sunsite.berkeley.edu/CurrentCites/
Why scan dozens of journals for those few choice tidbits when a group of people will do it for you?
D-Lib (Forum and Magazine) - http://www.dlib.org/
D-Lib Magazine: Essential for anyone tracking DL developments.
Web4Lib (for library-based World-Wide Web managers) - http://sunsite.berkeley.edu/Web4Lib/
Someone called it the "pulse of librarians online". I won't argue with that.
ZDNet Anchordesk - http://www.zdnet.com/anchordesk/
ZDNet Anchordesk: The best thing I've seen for keeping up with computer technology, although they sometimes lean a bit too far to games and toys for my taste. The nice thing is a summary drops into your mailbox on a frequent basis, and based on the capsule summaries you can either go to the site or not. A brief introductory piece sends you forward to the full article in one of the Ziff-Davis publications.
Library & Information Technology Association