One of the coolest entries that I've seen in the Greener Gadgets Design Competition is Recompute, a cardboard-housed PC. The Recompute design does away with many of the not-so-eco-friendly materials that go into computer manufacturing, such as ABS plastic, instead using corrugated cardboard for the housing.
Because corrugated cardboard is recyclable, and Recompute can be assembled with low-impact processes, the designer, Brenden Macaluso, might have just started the ball rolling for a truly 'green' computer. Recompute can be completely disassembled by hand at the end of its lifecycle, making it easy to recycle the individual components, and the design has 8 USB ports, letting you add external components as needed, instead of built-in.
This is a functional computer, built with off the shelf components, and because it's just the 'box', you can reuse a keyboard and monitor from your previous PC, again cutting down on unnecessary waste. The system pictured uses an Intel Core Duo CPU with 2GB RAM, and the only components inside are the motherboard, a hard drive, and the power supply.
It's refreshing to see a design that takes into account the manufacture, use, and disposal of the product, not simply one aspect of being green. I really hope this design goes into production, so head over to Core77 and vote for Recompute!