Listmania!
A complete Hold'em Education
By an Amazon.com customer
The Theory of Poker:  A Professional Poker Player Teaches You How To Think Like OneThe Theory of Poker: A Professional Poker Player Teaches You How To Think Like One by David Sklansky
Buy new: $19.77 / Used from: $10.49
Must have. Fundamentals for a solid foundation.
Winning Low-Limit Hold'emWinning Low-Limit Hold'em by Lee Jones
Buy new: $16.47 / Used from: $9.94
Good to have. Probably your next book if you are starting out and are going to play in low limit.
Hold'Em Poker for Advanced Players (Advance Player)Hold'Em Poker for Advanced Players (Advance Player) by David Sklansky
Buy new: $19.77 / Used from: $1.99
Must have. Hands down the worst written poker book of all time. Unfortunately, it has critical concepts on every page. You'll just have to do like the rest of us - read and reread until this book is firmly incorporated in your mind.
Harrington on Hold 'em Expert Strategy for No Limit Tournaments, Vol. 1: Strategic PlayHarrington on Hold 'em Expert Strategy for No Limit Tournaments, Vol. 1: Strategic Play by Dan Harrington
Buy new: $19.77 / Used from: $15.93
Must have for no-limit. Whether tournaments or not, this give fantastic strategy for No-limit.
Harrington on Hold 'em Expert Strategy for No Limit Tournaments, Vol. 2: EndgameHarrington on Hold 'em Expert Strategy for No Limit Tournaments, Vol. 2: Endgame by Dan Harrington
Buy new: $19.77 / Used from: $15.00
Must have for no limit tournaments. This is critical if you are going to play tournaments. Less useful for cash games.
Harrington on Hold 'em: Expert Strategies for No Limit Tournaments, Vol.  III--The Workbook (Harrington on Hold'em)Harrington on Hold 'em: Expert Strategies for No Limit Tournaments, Vol. III--The Workbook (Harrington on Hold'em) by Dan Harrington
Buy new: $19.77 / Used from: $15.99
Good to have. This one is good to have along with the other Harrington Books I & II.
Doyle Brunson's Super System 2: A Course in Power PokerDoyle Brunson's Super System 2: A Course in Power Poker by Doyle Brunson
Buy used from: $8.20
Must have for no limit. This is much the same as his first book, but has some added features.
No Limit Hold 'em: Theory and PracticeNo Limit Hold 'em: Theory and Practice by David Sklansky
Buy new: $19.77 / Used from: $13.80
Must have for "Deep Stack" cash games or tournaments. Sklansky has done it again. This book clarifies some concepts from Brunson's super system book. When reading this, try to remember that many of his concepts are for "Deep Stacks".
Phil Gordon's Little Green Book: Lessons and Teachings in No Limit Texas Hold'emPhil Gordon's Little Green Book: Lessons and Teachings in No Limit Texas Hold'em by Phil Gordon
Buy new: $15.64 / Used from: $8.49
Very good to have. Reinforces concepts from other books and sheds new light in several areas.
Phil Gordon's Little Blue Book: More Lessons and Hand Analysis in No Limit Texas Hold'emPhil Gordon's Little Blue Book: More Lessons and Hand Analysis in No Limit Texas Hold'em by Phil Gordon
Buy new: $16.38 / Used from: $8.95
Very Good to have. Reinforces concepts from his Green book and other poker books.
Phil Hellmuth Presents Read 'Em and Reap: A Career FBI Agent's Guide to Decoding Poker TellsPhil Hellmuth Presents Read 'Em and Reap: A Career FBI Agent's Guide to Decoding Poker Tells by Joe Navarro
Buy new: $13.64 / Used from: $8.12
Must have for live play. This book has replaced Mike Caro's book on tells. Caro's book was useful, but this book goes much further.