WP_Query::is_page()
Is the query for an existing single page?
WordPress 3.1.0 Hooks, Functions, Classes and Methods
Page 10
WP_Query::is_paged()
Is the query for a paged result and not for the first page?
WP_Query::is_post_type_archive()
Is the query for an existing post type archive page?
WP_Query::is_preview()
Is the query for a post or page preview?
WP_Query::is_robots()
Is the query for the robots.txt file?
WP_Query::is_search()
Is the query for a search?
WP_Query::is_single()
Is the query for an existing single post?
WP_Query::is_singular()
Is the query for an existing single post of any post type (post, attachment, page, custom post types)?
WP_Query::is_tag()
Is the query for an existing tag archive page?
WP_Query::is_tax()
Is the query for an existing custom taxonomy archive page?