NSLU2 aka Slug
The Slug is cool, I use mine as a Solaris JumpStart server.
Cost about GBP55 plus another GBP55 for the 160G USB disk.
I even had to install a full build environment on it so I could fix a bug in the tftp server.
I used it to install a whole bunch of Solaris machines, including Solaris 8, 9, 10 and 10x86
http://www.pbase.com/image/87845116