Since Kelly isn't stumping too hard for the Dummies book, I'm going to add my two cents without fear of offending him and say that in my experience the Dummies computer books are a waste of money. Yes, they do inject a little humor into the book, but the amount of real information for each dollar spent is minimal compared with Pogue's books.
Over the years I have done much of my computer self-education via books. I have read a fair number of titles from both the Dummies and Pogue and the typical Dummies book will have about 1/10 of the info contained in a Pogue book. Plus Pogue is a better writer than most computer book authors, and the indexes are more detailed in his books than the Dummies line.
Considering that
"Mac OS X: The Missing Manual (Panther Edition) is less expensive than the Dummies book, it's a no brainer for me...
I received a copy of Pogue's Panther book a few days ago, and, as usual, it meets all my expectations and more. And even though the Dummies books trade on their easy readability when covering complicated topics, Pogue generally does a much better job of explaining things. You may read a Dummies book once and get something out of it, but a book from Pogue will likely become a reference that you will return to when faced with a problem.
The Dummies books were a cute idea at one time, but at least in the computer genre they are too little substance for too much money.