As far as I can tell, my N800 is fine. I don't think the meltdown damaged the notebook computer either, but I haven't actually tested the USB port yet.

I'm simply happy that my wife and I were in the room when the adapter apparently shorted out. The strong smell of melting plastic came on suddenly, and the adapter was hot when I pulled it from the notebook computer. I've often left this adapter unattended, connected to an A/C-to-USB wall wart to charge my N800 in the past, and I can't help but think the adapter may have started a fire if we hadn't been there this time.