FWIW, I always find that I have to add a
<br clear=all /> tag to the Sidebar Login plugin after the
</div> tag where it gets the avatar. Otherwise the display looks like a mess with the links trying to wrap around the image. So, the line ends up looking like this:
echo '<div class="avatar_container">'.get_avatar($user_ID, $size = '38').'</div><br clear=all />';
If anyone else is experiencing this, that's how you fix it.