The Loop – Last Post / Next & Prev

Hey

I’ve got something in the loop to change the class of post 3 – there are 3 posts per page, so the last one on the page.

Which is fine but…If there are less than 3 posts then it doesn’t change the last post (to remove horizontal a line), which there will be on some archives for some categories / tags pages.

Any idea so I can target exclusively the LAST post on the page..not post #3?

I’ve tried a few code bits from other forum posts but can’t work it out ?? Here’s the loop..

<?php if (have_posts()) : ?>
<?php } ?>
<ul class="blog">
	<?php $postnum = 1; ?>
	<?php while (have_posts()) : the_post(); ?>
	<?php if ($postnum ==3) { ?>
		<li class="post_last">
			Last Post
		</li>
	<?php } else { ?>
		<li class="post">
			Post
		</li>
	<?php $postnum++; ?>
<?php } ?>
<?php endwhile; ?>
</ul><!-- end blog -->

Also, I’ve got next and previous links set up in the archives for pagination..

<ul class="next_prev">
    <li class="prev">
        <?php previous_posts_link('&laquo; Newer Posts') ?>
    </li>
    <li class="next">
        <?php next_posts_link('Older Posts &raquo;') ?>
    </li>
</ul>

Again, if there are less than 3 posts then it still obviously outputs the following code..

<ul class="next_prev">
   <li class="prev"> </li>
   <li class="next"> </li>
</ul>

Is there any way I can write something to exclude the list altogether if there’s only 1 page of archives / no need for the links?

Help much appreciated

Thanks in advance
Boon.