What Ruby IDE do you prefer?
Have you tried Aptana? It's based on Eclipse and they have a sweet Rails plugin.
What is the best development environment for Ruby on Rails?
I don't think you need an IDE for RoR, but if you really need one, with with IntelliJ IDEA or Eclipse. But I find eclipse buggy for rails.
What IDE to use for developing in Ruby on Rails on windows?
Any good IDE for Ruby on windows?
Rubymine is the only real IDE I know of (trial for 30 days), but most of the people use a texteditor like Sublime Text, eventually expanded with addons for the language you program in.
I wouldn't advise Eclipse unless you are allready familiar with it, a lot to configure and slow.
You don't really need an IDE for debuging, take a look here.
Is there any good intellisense tool for coding Ruby?
The best one is of course RubyMine: http://confluence.jetbrains.net/display/RUBYDEV/RubyMine+EAP
What's the best available open source editor/IDE for Ruby?
NetBeans is the best. You can download the "ruby" version - so you have rails support out of the box. It has all the important features for me: debugging support, syntax highlighting, auto-formating, rake task runner, ./script/generate runner. In last three versions I used it - startup and running speed increased and number of critical bugs decreased.
I have tried Aptana, Radrails, vim with ruby scripts, jEdit with ruby support etc .. and I have settled for NetBeans. It's very easy to "pick up" for new developers ...
What IDE / Editor do you use for Ruby on Windows?
Netbeans IDE is quite good.
What IDE to use for developing in Ruby on Rails on Windows?
Try both NetBeans and RadRails for maybe a week each, then you can find which works best for you. The best advice is to learn your tool. If you are not checking out something new about your editor, something that could potentially save you time (regexp, etc) then you are doing yourself a huge disservice.
I have been using Eclipse/Aptana/RadRails and unlike Gaius have been pretty happy with it.
I recommend the Eclipse IDE for Java Developers from Eclipse Downloads: http://www.eclipse.org/downloads/
Then grab Aptana Studio, following these instructions.
When Eclipse restarts Aptana will have a view, click on rad rails and you are good to go. Just make sure you have ruby installed already, or it becomes a pain to resolve.
Can anyone recommend an IDE for developing ruby/cucumber tests
Rubymine has built-in support for Cucumber.
Does any one know good editor available in RoR for windows?