I reviewed this title several years ago and highlighted the excellent training material and structure it provides. My view on that remains. However, this book has literally 99% the same content and structure of the earlier editions, so if you are looking for new material you wil be disappointed. The software changes relating to the training examples are largely cosmetic, one or two modified dialogs and toolbars. Nothing of substance.
Also, there is no requirement to purchase this book to obtain the 180-day evaluation software (which is ArcGIS 10 Editor version). Indeed, it is no longer bundled with the book, you have to download the 3.9Gb file, but you also get the evaluation key, so this latest edition is unnecessary.
My advice is, save yourself a whole lot of money, buy an older version and obtain the software via download. There is so little change to the book you will not be disadvantaged. Amazon currently (Dec 2010) has used editions from $17.13.
ESRI Press could have provided an 'update' pdf of changes, but I doubt it would have got beyond a page!
IanO - UK