So I've decided after a few years away, that I want to get back into Ruby on Rails for some of my personal projects. What I'm wondering is what are the best resources to find out what the new features are in rails? I haven't really even touched Rails since 1.2 was new.
Oh yeah, and is TextMate still the defacto editor for RoR on the Mac, or has something better come along?
I found the book Agile Web Development With Rails (3rd edition) to be the most helpful to get me going again earlier this year. In particular it notes some concepts that have changed as well as introducing the new items.
Check out the official Rails Guides. These should provide a nice overview of Rails (if you are rusty) and are kept up-to-date with the latest versions.
You may want to check out Ryan Daigle's Edge Rails posts which covered features as they were added to the new versions. Use the dates to determine where to start and go through each one. He also has a PDF for $9 which covers upgrading to Rails 2.1.
I have also covered the changes on Railscasts. Check out the various tags for each version to see them: 2.0, 2.1, 2.2, 2.3.
Update: Thoughtbot blog has posted about upgrading to Rails 2.1 and 2.3.2.
Regarding editing, Textmate still seems to be #1 among the MacRails folks, the text-editing ones, at least.
Beyond that, there are some IDEs around now, if that's your preference. They're starting to become fairly not-awful, which is pretty impressive really. There are plenty of questions here that touch on the topic: try searching for "ruby rails ide"
The Ruby Toolbox is a great and fairly new resource for seeing what gems/plugins/tools are popular for various aspects of your application such as authentication, testing frameworks, search, etc. It's based on the number of watchers and forks each project has on GitHub, which is a reasonably good way of judging popularity.