One not-so-obvious candidate: JavaScript and HTML.

Pretty much every browser in existence supports JavaScript, so with nothing more than a simple text editor and your browser of choice you can be off and running. As far as beginning programming is concerned, JavaScript easily encompasses any programmatic constructs you'd need.

The best part is that the students can easily display the results of their test programs in HTML, either dynamically generated or just by manipulating some divs, textboxes, tables etc that they've written on their page. Additionally, an instructor could write a 'playground' bit of HTML and JavaScript, so all output variables are bound up and easy to access. At that point the student is free to focus on what really matters, his/her first logic routines. When the student has created his first masterpiece, sharing the accomplishment with parents/peers is as simple as sharing a link to their HTML file.

I think this has the potential to engage students much faster than observing console output or fighting with a front end like windows forms in VB or Swing in Java.

This is absolutely true -- I work for a pretty large web development shop, and over 30% of our client browsers are IE6. The corporate world just can't lay out the money to upgrade their customized browsers, rework intranet sites, etc.

Our management has decided to support IE6 for another year at least -- there is just no way we could justify losing 30% of our client base, no matter how many hoops we must jump through to get our client side working in IE 6/7/8, FF2/3/3.5 etc. The legacy of IE6 will remain with us for quite some time I'm afraid.

http://www.amazon.com/Pocket-Ref-Thomas-J-Glover/dp/1885071000

'Pocket Ref' is a conveniently sized book containing an absolutely outrageous amount of data. In 3-3/4" x 5-1/2" x 3/4" dimensions and around 500 pages, Thomas Glover covers topics from ASCII tables, to load bearing capacities of 2'x4's, to a comprehensive math and physics formula 'cheat sheet'.

I don't know if it is possible to exaggerate how useful this book is. Along with a decent calculator and a knack for solving practical problems, you will be unstoppable with the Pocket Ref at your side. McGyver certainly had a copy hidden in his shirt pocket.