Always use <?php ?> to
delimit PHP code, not the <? ?> shorthand.
This is required for PEAR compliance and is also the most portable
way to include PHP code on differing operating systems and setups.
Drupal code styles suggest avoiding the final closing ?>.
They do so as to minimize the chance of content being sent by whitespace (sometimes inserted by FTP clients) after the closing town, which may prevent proper sending of headers.
Does PEAR care either way? Is it OK to avoid the final closing PHP tag?