urgh... yes I've used it but I was hoping for something a little less 1980's. We can have multiple windows now ;-)

I find it useful to be able to see the current stack, drill into variables, view my code with syntax highlighting, and the current line all at the same time. It helps me understand where I am.

RubyMine is something you may want to look into then. While it's commercial, you can often get a free license if you work on an open-source project.

(I won a free license as a prize at a conference a few years back and it's really quite nice.)

There is an an emacs interface to ruby-debug. See http://bashdb.sourceforge.net/rdebug-emacs.html

The rewrite of ruby-debug for Rubinius currently supports syntax highlighting via CodeRay. See https://github.com/rocky/rbx-trepanning or https://github.com/rocky/rbx-trepanning/wiki/Terminal-Colors for how to set that up.

The github project Emacs interface for the newer series of debuggers is https://github.com/rocky/emacs-dbgr.

But as someone else pointed out, it sounds like you'd be happier using an IDE such as one from JetBrains, Aptana, or Eclipse.

Oh I wish somebody would bring that 1980 technology to Java / .NET.

It would make things so much easier for me.