People are asking for recommendations of a good CFMX book. I'd like to point out that Macromedia has written an excellent one: "Developing Macromedia ColdFusion MX Applications with ColdFusion Markup Language". It's 900 pages, and guess what? It's free! Seriously. It's just one of 10 books in the CFMX docs (including a "Migrating Macromedia ColdFusion 5 Applications", "Working with Verity Tools", "Administering Macromedia ColdFusion MX", and more).
The CFMX docs are an often overlooked gem. So many questions people ask are answered there. And everything new in CFMX is covered in the docs, as well as improved discussions about features that were available in CF5 (cfscript, query of query, verity--an entire new manual, and more).
The docs are installed free when you install CFMX. You should find them on your server at http://[yourserver]/cfdocs/dochome.htm. Note that this includes a handy search feature in the top right corner when looking at a page within one of the books, which can search across the entire docset.
This same set of HTML help is also available online at http://livedocs.macromedia.com/cfmxdocs/, and you can get them in PDF form at http://www.macromedia.com/support/coldfusion/documentation.html.
Finally, you can also buy them in print format for only $50 for the entire set (nearly 2000 pages), at http://dynamic.macromedia.com/bin/MM/store/US/product.jsp?category=/BooksVideos/Documentation/ColdFusionServer&type=FULL. That's a bargain, and it's available now.
Of course, like any book, there are often additions or corrections that must be considered. MM is good about that as well. See the “Documentation Update” (http://www.macromedia.com/v1/Handlers/index.cfm?ID=22811&Method=Full), and the “Documentation Additions” (http://www.macromedia.com/v1/handlers/index.cfm?id=22993&method=full).
The books do indeed cover most of the new features, but there are always hidden gems in the Release Notes (http://www.macromedia.com/support/coldfusion/releasenotes/mx/releasenotes_mx.html).
There is also substantial coverage of new features on the Macromedia Designer/Developer site (http://www.macromedia.com/desdev/mx/coldfusion/).
I'm not knocking all the fine books that are out or coming out on CFMX. Not at all. And certainly they may do a better job in some ways than the CFMX docs on some particular topic or approach. But don't dismiss the MM docs. They're really worth their price (especially being free, indexed, available locally and remotely.)