<http://www.radrails.org/> (Standalone download, or Eclipse plugins) At one time the standalone download was generally considered to be better than the Eclipse plugin, but I haven't checked back in quite a while.
Hence, I am not David, but I can tell you what he said regarding just such a question. At RubyConf last year, he basically said that with Ruby, a good text editor goes much further than it can, if you're programming Java. Also, the entire Rails core team uses TextMate. So, I'd give TextMate a little more time, before I switched to RadRails.
Ruby IDEs are getting better and better. I particularly like Textmate for Rails development, but it's only available for the Mac. The Eclipse plugin is pretty good too.
However, one feature I greatly miss is Refactoring support, and I mean something more than simple search & replace. It'll probably take some time to get a decent refactoring support for Ruby, given the dynamic nature of the language.
I prefer the look and feel of Textmate, its power, and minimalist appearance over RADRails. On a Mac machine I will use Textmate hands down but when it comes to windows or linux machine I will use RADRails no questions asked. RADRails is the perfect ide for those who are looking for an opensource multiplatform solution.
posted 13 years ago
It appears David hasn't been visiting this forum so heres a link to 37signal's blog