"Compare that to Ruby, where you can't even get a specification of the current state of the language for free."

Err.... http://www.ruby-doc.org/

"What do you use for Ruby on Rails?"

Textmate. :-)

http://macromates.com/

BTW, you might want to have a look at JRuby. While it's still pre-1.0, it's moving along nicely. It will allow you to leverage all your knowledge of the Java class libraries.