It's Okay to be Smart (www.itsokaytobesmart.com)
A PhD biologist and science writer. He also hosts PBS's "It's Okay to be Smart" PBS series. In this blog, he examines all aspects of life through a scientific lens.
The gold standard in scientific news and education.
Science Blogs (scienceblogs.com)
Compiles over 60 science bloggers. It covers a huge variety of scientific issues from different, brillaint perspectives.
Institute of Physics (www.iopblog.org)
Official blog of the institute of physics; don't expect any frills here, just a discussion of physics from a very professional perspective.
Reddit Science (www.reddit.com)
Redditors share scientific stories, the latest research, and to discuss it all.
Retractiion Watch (retractionwatch.com)
Publishes news of scientific journal retractions. The goal is to keep scientific journalists improving.
Run by a neuroscientist and a cognitive scientist, and they definitely have fun in this blog about the mind.
The Loom (phenomena.nationalgeographic.com)
Carl ZImmer, contributer to New York Times and National Geographic runs this blog, which covers a variety of scientific issues.
Science Daily (www.sciencedaily.com)
Offers regular updates on scientific research. Besides traditional scientific topics, they also have a fun "quirks" page that looks at the quirkier science news.
Last Word on Nothing (www.lastwordonnothing.com)
It Began as a project among many scientists to write stories. Their work covers both sciecne and the art of science writing.
Thirty-Seven (thirtyseven.scientopia.org)
Run by Raychelle Burks, Thirty Seven examines crime, chemistry, and culture.
Brings together staff writers and independent writers to cover a diverse array of science issues.
Science Mag (www.sciencemag.org)
Keeps you up to date on the latest science news.
Discover Magazine (discovermagazine.com)
Brings you news and features on all things science.