General
Life, the Universe & Everything Else (Winnipeg Skeptics)
The Skeptics’ Guide to the Universe (SGU Productions)
The Reality Check (The Ottawa Skeptics)
Oh No, Ross and Carrie! (Carrie Poppy & Ross Blocher)

Medicine
QuackCast (Dr. Mark Crislip)

Religion
Reasonable Doubts (Jeremy Beahan, Luke Galen, Dave Fletcher, Justin Schieber)
The Atheist Experience (The Atheist Community of Austin)
The Non-Prophets (The Atheist Community of Austin)
Godless Bitches (The Atheist Community of Austin)
Ask an Atheist (Seattle Atheists et al.)

Evolution and Other Sciences
Are We Alone? (SETI Institute)

General
The Demon-Haunted World, by Carl Sagan
50 Popular Beliefs That People Think Are True, by Guy P. Harrison
Extraordinary Popular Delusions and the Madness of Crowds, by Charles Mackay

Medicine
Bad Science, by Dr. Ben Goldacre
Trick or Treatment, by Drs. Edzard Ernst (MD, PhD) and Simon Singh (PhD)

Religion
Why Are You Atheists So Angry?, by Greta Christina
Misquoting Jesus, by Bart D. Ehrman
The Missionary Position, by Christopher Hitchens
Breaking the Spell, by Daniel C. Dennett
Godless, by Dan Barker
Losing My Religion, by William Lobdell
Irreligion, by John Allen Paulos
50 Reasons People Give for Believing in a God, by Guy P. Harrison

Evolution and Other Sciences
Bad Astronomy, by Phil Plait
The Greatest Show on Earth, by Richard Dawkins
The Selfish Gene, by Richard Dawkins
The Blind Watchmaker, by Richard Dawkins

Other
Top Secret: The Truth Behind Today’s Pop Mysticisms, by Robert M. Price
Innumeracy, by John Allen Paulos
Quirkology, by Richard Wiseman
Paranormality, by Richard Wiseman

Local Blogs
The Winnipeg Skeptics Blog
Skeptic North
Startled Disbelief (Gem Newman)
Leave Faith Behind (Jeffrey Olsson)

General
Swift (James Randi Educational Foundation)
The Rogues Gallery (The New England Skeptical Society)
Skepchick (Rebecca Watson et al.)

Medicine
Neurologica (Dr. Steven Novella)
Science-Based Medicine
Bad Science (Dr. Ben Goldacre)
Respectful Insolence (Orac)

Religion
Pharyngula (PZ Myers)
The Atheist Experience (The Atheist Community of Austin)
Greta Christina’s Blog (Greta Christina)

Evolution and Other Sciences
Bad Astronomy (Phil Plait)
The Panda’s Thumb (The Patrons of the Panda’s Thumb)
Skeptical Science: Getting Skeptical About Global Warming Skepticism (John Cook et al.)

General
Skeptics on the .Net
The Skeptic’s Dictionary (Robert T. Carroll)
Snopes (Barbara and David P. Mikkelson)

Medicine
PubMed (United States National Library of Medicine)
QuackWatch (Dr. Stephen Barrett)
What’s the Harm? (Tim Farley)
Jenny McCarthy Bodycount (Derek Bartholomaus)

Religion
Iron Chariots (Matt Dillahunty, Russell Glasser, et al.)
The Skeptic’s Annotated Bible (Steve Wells)

Evolution and Other Sciences
Talk Origins (Based on the talk.origins Newsgroup)
Climate Change Evidence Page (NASA)

Other
Stop Sylvia Browne (Robert Lancaster)
So You’ve Had a Threatening Letter: Bloggers and Libel Law (Sense About Science; PDF)