I run M0n0wall on a WRAP at home but use more power
at work.  I recycled a 1U web server with a P4 workstation
board by adding a laptop chip, a piece of compact flash and
a 4-port NIC.  I unplugged everything except one of the fans
and one dimm.  It is not ugly, nor noisy, and it consumes
less than 50 watts.  It is a modern platform at 1.2 GHz, but
obviously the PSU fan and chassis fan give it more points of
failure than a WRAP.  Present uptime is 230 days.  If a fan
does stop, the BIOS will turn off the power.

	It might be too expensive to build such a box new at
retail prices but with the parts already on hand, I was only
out of pocket $60 for the CPU and $10 for the compact flash
adapter.

	My old firewall was a simple 486 NAT box which
loaded Linux and my configuration from a floppy disk into
16MB of RAM.  It ran for seven years and if it ever crashed
I don't remember it, despite its many potential points of
failure.  It was ugly but didn't make much noise.  At 60
watts it certainly wasted power, but hardly at the rate of a
glutton.

	If a 5 watt appliance meets your needs, it is
certainly the elegant and consciencious solution.  But the
critiques of recycling old hardware miss their mark when
stated too broadly and exaggerated.