Programmers are as passionate about the tools they use to write code as they are about which language the code is written in. There is typically a trade-off between speed and ease of use, in that the tools that are the fastest tend to require memorization of keystrokes and jargon; whereas the ones that are easier to use sacrifice efficiency for a more intuitive user experience.

There are several options available when developing Rails applications. A couple of popular simpler editors are Sublime Text (http://www.sublimetext.com) and TextMate (http://macromates.com). A few popular rich editors are RubyMine (http://www.jetbrains.com/ruby), Aptana (http://www.aptana.com), and Visual Studio with Ruby in Steel (http://sapphiresteel.com).

I've tried them all, and personally tend to oscillate between RubyMine and Sublime Text, depending on the project. If I'll be doing a lot of visual debugging, I'll use RubyMine. But for most projects, I find the speed and intuitive features...