As an Internet addict and student of science, I have quite a few sites I often visit for knowledge and/or entertainment. Here are a few.
Science-Based Medicine ~ Several medical doctors write for this daily blog on medicine firmly based in science.
Bad Astronomy ~ Phil Plait's blog about astronomy, physics, and science in general.
Skepchick ~ A group of individuals who blog about science, feminism, and critical thinking.
Bad Science ~ Dr. Ben Goldacre's blog that takes on big pharma, general woo, and, of course, bad science.
Cassini Images ~ A NASA site that provides the most recent images from the Cassini probe that is currently orbiting Saturn.
Journal of Visualized Experiments
Scientific American: Observations
Wired Gadget Lab
Saturday Morning Breakfast Cereal
Style High Club
ELLE Street Chic
Wil Wheaton's blog
An EE Girl on the Go
Vagamunda: Tales from the Traincase
Expertise in Results
South Park Avatars