I'm looking to pick up a few books on RoR to help teach myself how to build a scalable RoR app. I have read the RailsSpace book, and am starting the Rails Way book tonight.
Some topics of interest are:
Agile Web Development With Rails is always a good starting point for Rails newcomers.
I really liked this book because of it's example driven approach to teaching you the framework. They walk through building an application step by step which I think really helps you get your head around the gist of the Rails framework.
After Agile Web Development with Rails, my favourite is Practical Rails Projects, which goes over rails by 'developing' several projects, using features such as web services, REST, javascript, etc.
I quite liked the Rails Recipes books, as they're a good collection of best practices. For learning rails, the Agile book is the standard.
I agree with "The Rails Way". It just covers more advanced topics than most other books.
I started with "Agile Development With Rails" and I hear good things about the SitePoint book "Simply Rails 2". The thing to consider, especially with Rails, is to make sure that the edition you're reading is relevant. Rails moves extremely fast and I've found that finding accurate, timely documentation is hard. It's a mash of blogs and random wiki documentation across multiple websites. Take the time to make sure you're getting the right documentation about the right version.
Rails Recipes and Advanced Rails Recipes are great straightforward books for just getting things done. I've just started reading The Art of Rails which covers some more advanced topics such as meta-programming, API design and RSpec. I'm enjoying it so far.
This question has been asked in similar forms a few times on StackOverflow. Here's a link to one similar question.
I'm currently reading;
They're all good, (probably listed in order of complexity)
Agile Web Development With Rails is my favorite book for rails!
If you need more information use google :)