> I'm working in Windows and I'm just not sure what set of tools
> will work decently

You might want to take a look at the Zeus for Windows programmer's
editor:

   http://www.zeusedit.com/features.html

> - tabbed view of open files
> - project view or a folder view of files

These come as standard.

> - good syntax highlighting
> - auto indentation

Zeus has auto indentation, code folding and syntax highlighting for
Ruby.

> - code completion

The code completion is fully configurable so it may or may not be
possible to make it work for Ruby.

For example this is how C#/Mono code completion is configured:

  http://www.zeusedit.com/forum/viewtopic.php?t=211

and here is the Microsoft MFC code completion is configured details:

  http://www.zeusedit.com/forum/viewtopic.php?t=185

But if you find that it does not work for Ruby feel free to raise a bug
report.

> - works for .rb and .rhtml files
> - support for rails

Zeus if highly configurable so it should be possible to do this.

> - debugging

Zeus does have limited debugging support but it is definitely not one
of it's strong points :(

> Does anyone have suggestions on what I should be looking at?

One thing to note is Zeus by designed is language neutral meaning it
does not favour any one particular language.

It see no reason why it should not be possible to configure Zeus for
Ruby, but don't expect to find all these features "out of the box", so
to speak.

Note: Zeus is shareware (45 day trial).

Jussi Jumppanen
Author: Zeus for Windows