A few changes to Pando's script make it generic and without the DBA dependency:

Code:
set termout on
set head off feedback off verify off termout off
spool /tmp/drop_all.sql
Select 
  Rtrim('drop '||object_type||' '
    ||object_name||decode(object_type,'TABLE',' cascade constraints')
    || ';' )
from user_objects
order by object_name
/
spool off

set head on feedback on verify on

spool /tmp/drop_all.log

set echo on
@/tmp/drop_all.sql
spool off

set echo off

set pagesize 14 termout on
But it does not detract from the fact that the original post requested how to remove all tables and not all objects. Unless the poster is clear in thier requirements than confusion like this is bound to occur.

Regards