best way to use custom taxonomy, post type and meta in a job system

When the question comes to what to use Post Type, Taxonomies, custom fields ?
I find that the understanding what each one of them stands for helps make the selection easier so i use:

• Post types – for all major data records that need/not to be displayed or queried.
• Taxonomies – for grouping posts/custom records together (with children) , helps a lot in queries.
• Custom fields – for extra data that needs to be specific per post/custom record ,maybe even to help in queries.

So in your case i would use:

• job title – post title
• description – content
• location – Custom Taxonomy (hirirchal)
• sector – Custom Taxonomy
• salary start – post meta
• salary end – post meta
• contact person – post meta
• skills – post meta maybe even a custom taxonomy (depends on your needs)

As for searching based on a mix of them its actually easier then it sounds :

$args = array(
    'post_type' => 'job',
    'posts_per_page' => -1,
    'tax_query' => array( //this is for taxonomies
        'relation' => 'AND',
        array( //For location we use
            'taxonomy' => 'location',
            'field' => 'slug',
            'terms' => array( 'florida', 'san-antonio' )
        ),
        array(//for sector we use
            'taxonomy' => 'sector',
            'field' => 'slug',
            'terms' => array( 'it' ),
            'operator' => 'NOT IN'
        )
    ),
    'meta_query' => array( //this is for post meta
       array(//lets say 10000 and above
           'key' => 'salary_start',
           'value' => array(10000),
           'compare' =>  '>=',
           'type' => 'NUMERIC'
       )
   )
);
$query = new WP_Query( $args );