Show hide elements on anchor click in a different container

You need to use a common naming convention for the div and the links like so:

<ul id="bannerList" class="list">
    <li>Type
        <ul>
            <li><a href="#" id="link-1">Flash banner1 120x600</a></li>
        </ul>
    </li>

    <li>Other Type
        <ul>
            <li><a href="#" id="link-2">Flash banner2 120x600</a></li>
        </ul>
    </li>
</ul>

<div id="bannerTarget">
    <div class="vert" id="div-1">alpha</div>
    <div class="horiz" id="div-2">one</div>
    <div class="horiz" id="div-3">two</div>
    <div class="horiz" id="div-4">three</div>
    <div class="horiz" id="div-5">four</div>
</div>

Your code then becomes:

$("ul#bannerList li a").click(function(e) {
    e.preventDefault();
    $('#bannerTarget > div').hide();
    var id = $(this).attr('id').replace('link-','');
    $('#div-'+id).show();
});

You can also achieve the same without using ID's but you'll need to keep the link order and the div order the same:

$("ul#bannerList li a").click(function(e) {
    e.preventDefault();
    $('#bannerTarget > div').hide();
    var link_index = $(this).parent().index();
    $('#bannerTarget > div').each(function(){
        if( $(this).index() == link_index ){
            $(this).show();
        }
    });
});