1. Timex TMX2
The ultimate combo: With 64MB aboard, the TMX2 transforms from wristwatch to pendant to carabiner. Price: $150.
2. CenDyne Gruvstick
Pop the 128MB Gruvstick (or Innogear Duex, below) into a USB port for easy MP3 transport. Both display artist and track information and cost $179.
3. Bantam BA800
Your pictures meet your music with the 256MB BA800—it incorporates a 1.8-inch color display. Price: $299.
4. Creative Labs Nomad Zen
Plug it into a USB or Firewire port for ultrafast downloads to its 20GB, 8,000-song hard drive. Price: $350.
5. Sonic Blue Rio S35S
A rubber grip, one-button navigation, FM radio, 128MB and armband make it a perfect workout companion. Price: $200.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.