SERVER 2003 DIRECTORY SETUP

HI , I HAVE A COMPANY THAT HAS 5 DIVISIONS WITH A CENTRAL ACCOUNTING DEPARTMENT . I WANT EACH DEPARTMENT TO HAVE THEIR OWN SPACE ON THE SERVER.DO I PARTION SEPARATE DRIVE OR CAN I JUST CREATE FOLDERS WITH QUOTA ON THEM . I ALSO WANT THEM TO LOGIN WITH MAPPED DRIVES TO HOME FOLDERS AND SHARED FOLDERS . iM NEW TO ALL THIS I HAVE WINDOWS 2003 SERVER WITH ONE DOMAIN AND 50 WORKSTATIONS.