Stuff I've already done:

ifdown
ifup
rebooted

root@neoharvey:/home/inthane# ifconfig eth0\neth0      Link encap:Ethernet  HWaddr 00:13:D4:E2:96:F8\n          inet addr:192.168.0.2  Bcast:192.168.0.255  Mask:255.255.255.0\n          inet6 addr: fe80::213:d4ff:fee2:96f8/64 Scope:Link\n          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1\n          RX packets:54612 errors:0 dropped:0 overruns:0 frame:0\n          TX packets:45763 errors:0 dropped:0 overruns:0 carrier:0\n          collisions:0 txqueuelen:1000\n          RX bytes:44464101 (42.4 MiB)  TX bytes:6055544 (5.7 MiB)\n          Interrupt:23\n\nroot@neoharvey:/home/inthane#

System is running on DHCP, cleared out DNS entries in the System->Administration->Networking->DNS tab. There's a bunch of IPv6 entries in the Hosts tab, and nothing else. The WinXP VMWare session is running in bridging mode, so it gets a different IP address; I think it's 192.168.0.3.

The one thing that has changed since before is that this machine used to sit at 192.168.15.2, gateway of 192.168.15.1, which then fed into the 192.168.0.1 subnet. This was done because a) I've got a Vonage phone, b) the DSL router only had one ethernet port, and c) I didn't have a network hub.