Well my new, cheap, generic USB to ethernet dongle 'just works', excellent! It was about a fiver from Lambdatek (along with some other stuff to avoid carriage being too significant).
It's branded "Dynamode" USB-NIC-1427-100 if anyone is interested.
It means I can add extra NICs to my little Acer Aspire Revo to my heart's content, I only need the one for the moment.
By the way I have Ubuntu Server 9.10 (last release candidate) installed on the Revo, went without a hitch. I tried xubuntu but that fell in a heap, I suspect the display drivers are not fully up to it yet and, as I don't really need X, I just went for the server installation.
Next to configure it to actually start doing useful things so I can turn my desktop machine off when I'm not using it and the rest of our little network will continue to be happy.