Get array of categories/tags/custom taxonomy objects (as opposed to just outputting html or a list), for further manipulation. This is a slightly modified version of wp_list_categories() - but saved in functions.php!

gistfile1.php

function wp_get_categories( $args = '' ) {
    $defaults = array(
        'show_option_all' => '', 'show_option_none' => __('No categories'),
        'orderby' => 'name', 'order' => 'ASC',
        'style' => 'list',
        'show_count' => 0, 'hide_empty' => 1,
        'use_desc_for_title' => 1, 'child_of' => 0,
        'feed' => '', 'feed_type' => '',
        'feed_image' => '', 'exclude' => '',
        'exclude_tree' => '', 'current_category' => 0,
        'hierarchical' => true, 'title_li' => __( 'Categories' ),
        'echo' => 1, 'depth' => 0,
        'taxonomy' => 'category'
    );

    $r = wp_parse_args( $args, $defaults );

    if ( !isset( $r['pad_counts'] ) && $r['show_count'] && $r['hierarchical'] )
        $r['pad_counts'] = true;

    if ( true == $r['hierarchical'] ) {
        $r['exclude_tree'] = $r['exclude'];
        $r['exclude'] = '';
    }

    if ( !isset( $r['class'] ) )
        $r['class'] = ( 'category' == $r['taxonomy'] ) ? 'categories' : $r['taxonomy'];

    extract( $r );

    if ( !taxonomy_exists($taxonomy) )
        return false;

    $categories = get_categories( $r );
    return $categories;
}