I've updated to the latest OS2008 firmware and my N800 is working better than ever! The power on issue seems to have been fixed and the web browser does a much better job of rendering webpages.

The only downside is that applying the firmware will reset the device to factory settings. A bit of a pain, but worth it for a device that is working as expected.

Thanks to the maemo group and nokia who are both in my good books right now.