What Ide/Editor Do You Use for Ruby on Linux

What Ruby IDE do you prefer?

Have you tried Aptana? It's based on Eclipse and they have a sweet Rails plugin.

Linux supported IDE for Ruby on rails development

NetBeans is pretty good.

What IDE / Editor do you use for Ruby on Windows?

Netbeans IDE is quite good.

Ruby and linux, preferred setup?

I use Vim on both Windows and Linux for development in Rails (we have to use Windows in work, and I only use Linux at home). The environment is almost exactly the same for both platforms. Especially important for me is easy navigation between the various Rails components - from Controllers to views, partials and models, and quick navigation to test files.

Here are the plugins I use:

Vim Rails by Tim Pope. The :R, :A and gf commands are the ones I use mostly for navigation.
NERDTree for a project/explorer view.
NERDCommenter for easy multi-line commenting.
FuzzyFinder and "FuzzyFinder - Textmate" - allows you to quickly find files based on portins of a file name.
Ctags
Bufexplorer
dbext for executing SQL commands and getting the results in a Vim buffer.
Ack and the ack plugin for a better grepping experience from within Vim.
VividChalk colour scheme.

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?

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 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.

Free Linux text editor with syntax highlighting

Also Gmate is nice. It's Gedit with a number of plugins which make it behave like textmate.

https://github.com/gmate/gmate

Is there an IDLE-like editor for ruby on Windows or Ubuntu?

Many thanks for all the suggestions, though having tried multitudes of editors, the option I've went with is Geany.
http://www.geany.org/

I couldn't get ScITE to work properly with standard input on either Windows or Ubuntu.
Ruby is a great language that could also be attractive to absolute beginners, however, the fact that the ruby installer does not include a basic editor that can be used in a self contained manner (to write and run scripts) really hinders its use for beginners.

This struggle to find an editor that could be used for writing and running ruby scripts almost had me resorting to python!