What Ruby IDE do you prefer?

RubyMine from JetBrains. (Also available as a plugin to IntelliJ IDEA)

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

Redcar has been getting some attention lately, as well. Still early in its life, but it shows promise.

On Mac OS X, TextMate is a godsend.

The latest Netbeans IDE (6.1) has a pretty solid Ruby support.

You can check it out here.

RubyMine is so awesome. Everything just works. I could go on and on. Code completion is fast, smooth, and accurate. Formatting is instantaneous. Project navigation is easy and without struggle. You can pop open any file with a few keystrokes. You don't even need to keep the project tree open, but it's there if you want. You can configure just about any aspect of it to behave exactly how you want.

NetBeans, Eclipse, and RubyMine all have more or less the same set of features. However, RubyMine is just so much more cleanly designed and easy to use. There's nothing awkward or clunky about it. There are all these nice little design touches that show how JetBrains really put thought into it instead of just amassing a big pile of features.

Incidentally RubyMine can do a lot of the things that Vim can do like select and edit a column of text or split the view into several editing panels with different files in them.

NetBeans has some really solid Ruby support.

I have used Komodo and it's pretty good. I use TextMate now.

For very simple Linux support if you like TextMate, try just gedit loaded with the right plugins. Easy to set up and really customizable, I use it for just about everything. There's also a lot of talk about emacs plugins if you're already using that normally.

Gedit: How to set up like TextMate

NetBeans is good because you can use it on Windows and Mac OS X.

Aptana more or less is RadRails, or it's based on it. I've used it, and it's really good, but it does have some problems. For instance, it breaks the basic search dialog on my system (giving a raw java exception to the end user), and it clutters the interface with add like notices and upgrade bars and news feeds and...

But all in all it's pretty good, especially its editors (ERB, HTML/XML, ...) are top notch.

I prefer TextMate on OS X. But Netbeans (multi-platform) is coming along quite nicely. Plus it comes with its IDE fully functional debugger.

Textmate on osx

E Text Editor is great (TextMate compatible sort-of-clone for Windows).

I started out using gEdit (ubuntu user), but even with all the plugins and modifications (class/file browser, terminal, darkmate scheme, etc, etc) it still always seemed to come up short. I've also tried like hell to get Aptana RadRails and Studio to work, but none of them ever really seemed to sync up with my workflow. I've even tried using Eclipse, but again, it just didn't work for me.

RubyMine also seemed like it would be great, but I found it to be way too buggy, even after the upgrade to 3.0.

So far, my favorite Ruby editor is Komodo Edit. It's got syntax highlighting and can detect errors and recognize your code based on user-specified ruby versions. Syntax highlighting schema are easily customizable and easy on the eyes. There are some very nice plugins for git, it can have split-screen editors (love that feature), and a great file-browser. I really wish Komodo had built-in terminal (multiple terminal) support, but everything else about it I've really come to love, and haven't found anything better yet.

+1 for TextMate on Mac OS X.

See also answers to this question. I recommend trying NetBeans if you're on Windows.

I'd recommend NetBeans 6.1 too. Very nice IDE and makes working with Ruby a pleasure.

I started out with RadRails then moved to Aptana when they took it over, wasn't too bad. Got a macbook and have been using Textmate, never going back.