The server is running as root (that's how the maker designed it,) but I have full read-write access with any user, so long as it's not via the HTTP interface.
All the files are owned by root:pi, but the user peter (who has no ownership of the file at all) can access them just fine via cat or whatever.
UPDATE: just chmod'ed the ENTIRE /var/www directory (files AND folders) to 775, now everything works fine! `chmod -R 775 /var/www/`
(I can also run `chmod o-x` on the files themselves without breaking anything..)
I thought I'd triple-checked the permissions, but evidently not.. sorry..
P.S., is there any way to create an account or password-protect a username?