Texts
Here is a group of books and journals which have proven useful as general resources. Some are good introductions to philosophy or critical thinking, some are popular books on specific issues, and some just good reading. As the list grows we will organise it better (suggestions welcome). Links are to Amazon if you're interested...
PS Think about asking for an evaluation copy if ordering through a school (I've gotten a few free ones to keep that way)

Why People Believe Weird Things: Pseudoscience, Superstition, and Other Confusions of Our Time by Michael Shermer and Steven Jay Gould (Paperback - Sep 1, 2002)
A terrific book by Michael Shermer from American Skeptics. The name says it all.
Thinking through Philosophy: An Introduction by Chris Horner and Emrys Westacott (Paperback - Oct 2, 2000)
Great introductory text for students (and teachers). Love the double meaning.
Critical Thinking by Alec Fisher (Paperback - Nov 1, 2001)
Quite good all-round text. An introduction as it says.
The Art of Reasoning by David Kelley (Paperback - Feb 1998)
More advanced text and quite rigorous.
The
Philosophy Gym by Stephen Law (Paperback - Mar 1, 2004)
Really good book for hitting the main points of philosophy - very well explained.
Best of the
general science journals (with Scientific American).
Crimes
Against Logic by Jamie Whyte (Paperback - Sep 12, 2004)
Love it. Good stuff and easy to read. Lots of fallacies pointed out.

Understanding Arguments: An Introduction to Informal Logic by Robert J. Fogelin and Walter Sinnott-Armstrong (Paperback - Aug 16, 2004)
Really nice book focusing on informal logic.

Critical Thinking, Thoughtful Writing: A Rhetoric with Readings by John Chaffee, Christine McMahon, and Barbara Stout (Paperback - Jun 10, 2004)
Great for critical thinking in writing with many structured exercises.

Letter to a Christian Nation by Sam Harris (Hardcover - Sep 19, 2006)
A brutal application of reason to religion today. Well researched, documented and presented. Should scare the pants off you...