I'm after a cheap and cheerful box that I can use as a dedicated Untangle server.
This is what the hardware requirements are:
"# The Untangle Server needs a dedicated PC to run on.
* We recommend at least a Pentium 4 Processor (or a similar AMD Processor), 80 GB hard drive, 2 network cards, and 1 GB of memory.
* Additional hardware details
# The PC does not need an operating system - the Untangle Server installs its own operating system. "http://wiki.untangle.com/index.php/Hardware_Requirements