<div class="item">
                <div class="dbanner"><a target="_self" href="/yatirim/default.aspx"><img alt="" src="/banner/media/27/YKA1/gorsel.aspx"></a>
                    <h2 class="landing">Default Banner</h2>
                    <span class="text">Mevduat Fon Paketi</span></div>
                    <div class="clear"></div>
</div>    
<div class="item2">
                <div class="dbanner"><a target="_self"  href="/yatirim/default.aspx"><img alt=""  src="/banner/media/27/YKA1/gorsel.aspx"></a>
                    <h2 class="landing">Default Banner</h2>
                    <span class="text">Mevduat Fon Paketi</span></div>
                    <div class="clear"></div>
</div>    
<div class="item3">
                <div class="dbanner"><a target="_self"  href="/yatirim/default.aspx"><img alt=""  src="/banner/media/27/YKA1/gorsel.aspx"></a>
                    <h2 class="landing">Default Banner</h2>
                    <span class="text">Mevduat Fon Paketi</span></div>
                    <div class="clear"></div>
</div>

js

$(document).ready(function() {
    var bannerTextHeight = 0;
    $(".dbanner").each(function() {
        if (bannerTextHeight < $(this).height()) {
            bannerTextHeight = $(this).height();
        }
    });

    $(".dbanner").each(function() {
        $(this).css('margin-bottom', (bannerTextHeight - $(this).height()) + 20);
    });

});

Alttan 20 px boşluk bırakarak hepsini eşit seviyede tutar. Diğer style'ları senin vermen gerek bu haliyle koyarsan yanyana durmaz. Örnek;http://finansbank.com.tr/yatirim/default.aspx