There was a problem with my host, so I reinstalled WP.
First I tried a fresh install of 3.01. It worked, managed to install, but can get to WP-Admin, all I see is a blank page. This can't be a plug-in issue because there are no plug-ins.
Cleared out the directory, installed 2.9. This works.
Couldn't automatically upgrade to 3.01.
Did a manual upgrade and found my way back to the white screen of death.
I suspect the problem is with the host - how can I know?