NSLU2 and it's possiblities
The awesome little device from Cisco (fka Linksys) contains a ARM 133Mhz processor, consumes aroudnd 5 watt, has an 100Mb ethernet port and 2 USB ports.
To be filled in; (installing Debian)
Cool services to run (File-/ Print serving, DAAP Server, Apache, MySql)
Cool peripherals (Videorecording, Webcam, Mouse, LCD Display, Serial)