The smb.conf docs say:
When the connection request is made, the existing sections are scanned. If a
match is found, it is used. If no match is found, the requested section name is
treated as a username and looked up in the local password file. If the name
exists and the correct password has been given, a share is created by cloning
the [homes] section.

This worked under Samba 2.2.8, but when we upgraded to 3.04, the [homes] section
seems to get precedence.

If you are connecting as "testuser" and you have in the smb.conf

[testuser]
    comment =  testing
    admin users = testuser
    path = /tmp/testuser
    writeable = yes

[homes]
   comment = Home Directories
   browseable = no
   writable = yes

On a server w/out any homedirs we see:
[2004/08/20 14:21:35, 0] smbd/service.c:make_connection_snum(591)
  '/home/domain/testuser' does not exist or is not a directory, when connecting
to [testuser]

If both paths are valid, you will see files under the homedir path.