Variants of query_posts

query.php

// http://www.binarymoon.co.uk/2010/03/5-wordpress-queryposts-tips/

<?php
$query = 'posts_per_page=10';
$queryObject = new WP_Query($query);
// The Loop...
if ($queryObject->have_posts()) {
	while ($queryObject->have_posts()) {
		$queryObject->the_post();
		the_title();
		the_content();
	}
}
?>

<?php
// GOOD
// select 10 posts from category 1
$query = 'posts_per_page=10&cat=1';
$queryObject = new WP_Query($query);
// The Loop...

// BETTER
$query = array (
    'posts_per_page' => 10,
    'cat' => 1
);
$queryObject = new WP_Query($query);
// The Loop...
?>

<?php
// select posts ordered by comment_count
$query = 'orderby=comment_count';
$queryObject = new WP_Query($query);
// The Loop...
?>

<?php
// grab posts by post count ordered in descending order (most votes first)
$query = 'meta_key=vote_count&orderby=meta_value&order=DESC';
$queryObject = new WP_Query($query);
// The Loop...
?>

<?php
// grab 1 random attachment
$query = 'post_type=attachment&orderby=rand&posts_per_page=1';
$queryObject = new WP_Query($query);
// The Loop...
?>


$bmIgnorePosts = array();

/**
 * add a post id to the ignore list for future query_posts
 */
function bm_ignorePost ($id) {
	if (!is_page()) {
		global $bmIgnorePosts;
		$bmIgnorePosts[] = $id;
	}
}

/**
 * reset the ignore list
 */
function bm_ignorePostReset () {
	global $bmIgnorePosts;
	$bmIgnorePosts = array();
}

/**
 * remove the posts from query_posts
 */
function bm_postStrip ($where) {
	global $bmIgnorePosts, $wpdb;
	if (count($bmIgnorePosts) > 0) {
		$where .= ' AND ' . $wpdb->posts . '.ID NOT IN(' . implode (',', $bmIgnorePosts) . ') ';
	}
	return $where;
}

add_filter ('posts_where', 'bm_postStrip');