If you plan to use the $page or $is_front variables in a conditional statement here is a good thread (especially read the comments) that discusses the difference between the two variables.
Simply put $is_front is set only when you are on the front page of the site. The $is_front variable is not set for "listing" pages, e.g. if you click on a taxonomy term and get a listing of nodes classified under that taxonomy term.
$page is equal to 0 for all "listing" pages such as taxonomy term pages.
<?php if ($is_front): ?> <p>This will only appear on the front page.</p> <?php endif; ?>
<?php if ($page == 0): ?> <p>This will appear on listing type pages.</p> <?php endif; ?>