Numbering Posts

To give posts a continuous number in index pages or archives, try this little piece of code:

<?php
global $query_string;
  $all_post_query = new WP_Query($query_string.'&posts_per_page=-1');
    $count_posts = $all_post_query->post_count;
  $this_post_nr = 1 + $wp_query->current_post + (get_query_var('paged')?(get_query_var('paged')-1) : 0) * get_option('posts_per_page');
echo $this_post_nr.' of '.$count_posts.' in this selection of posts.';
?>

Place it within the loop;
condition: needs to be adjusted for any custom query.