1) Lonely Planet Thailand
2) Fodor's Thailand, 8th Edition: The Guide for All Budgets, Where to Stay, Eat, and Explore On and Off the BeatenPath
3) Travelers' Tales Thailand: True Stories
4) The Rough Guide to Thailands Beaches & Islands
5) Frommer's Thailand
6) To Asia with Love: A Connoisseurs' Guide to Cambodia, Laos, Thailand and Vietnam
7) Lonely Planet Thailand Islands & Beaches
8) Dk Eyewitness Travel Guides Thailand
9) Footprint Thailand Handbook, Fourth Edition
10) Lonely Planet Diving & Snorkeling Thailand
Personally, I would recommend Dk Eyewitness' Travel Guide.
The last time this edition was published was January 2002. However, Thai people originally from this exotic country have said that the content is both accurate and rich in describing the culture, religion, politics, music, sports, and festivals of the land, aspects of the country that are less sensitive to time.
For the latest hotels and restaurants, we would recommend the most popular guides, plus the upcoming AAA Essential Guide: Thailand (to be published on March 1, 2005 but can be ordered now).
Here's to healthy, adventuresome, soulful traveling!
~Jennifer