I understand the elements of nostalgia of people growing up around the 1980ies for the time when computers where new and exciting. Around that time, I thought myself programming in C and M68000 assembler on a Commodore Amiga and probably learned more in basic understanding about programming and computer architecture than during the years afterwards in engineering school. The home-computers of that era were hackable enough to encourage tinkering and simple enough to allow really getting to the bottom of how they worked. The gap between what could be produced by determined hobbyists and professional software publishers was not that great.
By today, computers have become so ubiquitous and commonplace that they are no longer considered exciting. Students today use computers in the form of PCs, tablets, game consoles or smart-phones for researching or writing as naturally as we used to use books, pen and paper or pocket calculators. But many of todays computer platforms are also much more complex, sophisticated, closed and don't invite to tinkering with the underlying technology. Children today are growing up in a way much more computer literate (as users) than any generation before, but may know or care much less about how computers actually work than their parents generation.
Maybe there is a natural cycle of when technology is attractive and inviting to hobbyists. While in the 60ies many teenage kids would be tinkering with old cars in the backyard, the grease monkey sub-culture has largely come out of main-stream fashion, as cars today just work and are sealed black-boxes which don't allow for much tinkering without access to proprietary diagnostic systems. For the same reason, tinkering with computers might have been a think unique to the end of the last century and might not come back despite efforts like the Raspberry Pi project.
For those of us interested in getting today's youth generation interested in information technology, the question remains on what would be the most suitable way. Maybe I am myself blinded by nostalgia, but I am optimistically hopefully for the impact of something like the Raspberry Pi, as it seems both sufficiently accessible and hackable. The bare-board without a case may help to encourage an interest to go beyond the surface of how computers work - even though the highly integrated SoC architecture allows less so than ever to understand computer architecture from a visual/physical reality.
From my limited experience, it seems important to avoid creating dumbed-down "toy technologies" without real-world usage when trying to get children and young people interested in technology. Instead, we should encourage the use of real-world technologies and platforms which are easily accessible, have a low barrier to entry learning curve and are open and flexible enough to encourage experiment for some applications which are cool and intriguing for today's generation.
Maybe today's generation would more likely tinker around with a mobile device than a desktop computer and programming education should start with the development of apps for mobile devices. Both Android and iOS platforms allow for relatively easy application development, even though the device platforms on which users can easily get their hands on tend to be closed and locked down for a variety of reasons. Android is free and open-source, but only to those who own a cellphone factory and not to the end-user who buys a smart-phone, maybe even subsidized through a carrier. Also the tool-chain for mobile development is quite heavy and requires access to a PC typically - self-hosted development on a mobile platform so far is not typically an option.
Another obvious choice would be web applications. The browser is increasingly becoming the real platform for which applications are written, abstracting hardware and operating system differences. Cloud platforms like Google AppEngine and similar alternatives have essentially a very low barrier to entry in both cost and complexity for building and running a web application on the Internet. The modern browser standards with HTML5, CSS & JavaScript present a powerful and feature rich environment for application development with a high level of abstraction. However, the level of abstraction is so high and so far removed from the physical reality of the underlying hardware that web programmers may never need or want to understand how computers actually work.
Another area with lots of exciting potential might be robotics. Robotics encourages or even forces a confrontation with the physical reality of the systems we are developing. Given the improvements in miniaturization and power efficiency of computing hardware, there is much exciting activity and progress in the field across commercial development, cutting edge academic research and even hobbyist activities. Givent the combination of low-cost, low-power small size for a decently powerful compute platform, robotics might be the real sweet-spot for the new Raspberry Pi board in computer literacy education.
From my experience as a judge on a FIRST robotics competition, kids of a certain nerdy/technical inclination can certainly be excited about building robots. I would love to see integration and interoperability of the Raspberry Pi board e.g. with the Lego Minstorms robotics toolkit.