Thanks Gordon,
I'm sick of router crashes, and not having decent packet dumps without reconfiguring, so a Debian box of some sort makes sense.
Agree about WiFi, but no dedicated access points here, and I'll be very annoyed if I reuse the existing router and discover it is the WiFi interface causing the current router to crash.
No GUI, that'll reduce the risk of XSS attacks. Just issuing a DHCP response claiming your host name is <script>blah... with a few comments in will pwn my current router if anyone tries it locally.