Pro Drupal Development is a great book if you want to get into the nuts and bolts and tinker with PHP code.  If you're not wanting to be that geeky about it, just wanting to set up a web site with Drupal and add features to solve various kinds of needs, 'Using Drupal' is a good book.

Or you could just wait a few months for Drupal 7 to come out, when it will sit up on its hind legs, initiate a Vulcan mind meld with you and create the site of your dreams effortlessly.  Hey, that's what I'm hoping for! 

...then I'd say get to know it thoroughly through the admin interface.

Learn how to install modules and themes. Learn how to construct your own node types using cck. Learn how to query and display nodes using views. Learn a bit about the most common contributed modules available from drupal.org and what they do - then when you want your site to behave in some strange way that core modules don't cater for, you might just have come across a module that will provide the functionality you need.

There's a good lullabot podcast outlining 40 popular drupal modules. An interesting listen for people like you and me who are new to drupal. They've recorded about 80 of these - starting in 2006 I think. It sounds like drupal has changed a lot since then. I listened to podcast number 2 yesterday and Jeff Robbins said something like, 'Has anyone out there tried a new module called views? I had a little play around with it and it seemed pretty useful.'

I also find screencasts good for beginner learning. Here's a link to some screencast links:
http://www.minezone.org/blog/2007/11/01/45-screencasts-to-get-you-kickin...

It was only after learning the basics that I began to wish for functionality that I thought couldn't be found in any of the modules. This was when I first turned to Pro Drupal Development - which I must say is not easy going. But it is the book to read if you want to become a drupal expert. My advice is to first get yourself situated, then read the book.

Mark