Unfortunately two of them are already old. A version of Programming Ruby updated for Ruby 1.9 now exists in PDF format and Agile Web Development With Rails will most likely be updated due to the recent 2.0 release of Ruby on Rails. Maybe Everyday Scripting With Ruby will be updated too soon, but I hope that all of them will still be of use to me. I only use Ruby and Ruby on Rails for my personal projects anyway, but I think that both of them — the language and the framework — make too much impact to be ignored.
Speaking of Ruby on Rails: I read that Hemnet, the major Swedish site for real estate ads, is using Ruby on Rails. Cool!
I bought Agile Software Development With Scrum in order to read one of the major works about Scrum. I really ought to have read it before by Scrum Master certification but I can admit I didn’t. Now it’s time to make up for that.
The reason for buying User Stories Applied is that I want to improve my skills in handling customer requirements. My current client is very fond of use cases but I don’t think that diminishes the value of the book in any way.