Here are some great websites/blogs that I follow on a regular or daily basis…

Network Related (routing, switching, etc)
Network Fun!!  (by Shane Killen)  –  An excellent technical blog to visit everyday!
NYC Networkers (run by William Zambrano)  –  Great resource plus Cisco Cert info!
AmyEngineer (run by Amy) – Lots of VoIP resources along with routing/switching

Security
Krebs on Security (by Brian Krebs)  –  Visit this site everyday! Just do it…
SANS (Systems Administration and Network Security)  –  Lots of great resources…
—Internet Storm Center  –  Daily blog on all things security
—SANS Reading Room  –  Huge collection of security documents
—Glossary of Security Terms
—Critical Security Controls  –  If you’re not sure where to start, then start here!!

Linux
CentOS  –  My favorite Linux distro
Redhat  –  My favorite Commercial distro…it is SOLID as a rock

Other
BIND  –  DNS server and related tools…highly recommended