Oh, philosophy! I know I have several books on the subject, so let me see what I have in my personal library here...
'How to Think About the Great Ideas' by Mortimer J. Adler
'A Brief History of the Paradox' by Roy Sorensen
'An Essay Concerning Human Understanding' by John Locke
'The Pocket Aristotle'
These are the books that I could currently dig up that I own, though I still have yet to read the ones by Sorensen or Locke, so I cannot really comment on their quality. The one by Adler, however, I have had a chance to read to completion and I thought it was a very thought-provoking read, as it goes through a wide variety of topics, such as truth/knowledge/opinion, emotion, love, good/evil, beauty, law, government, art and quite a few more. If nothing else, I would highly recommend this one of only on the grounds that it is sure to have at least one section that would perk your interest.
Happy reading!