<div id="header"></div>

<div id="main">
    <div id="navigation"></div>
    <div id="content"></div>
</main div>

<div id="footer"></div>

#main {
position: relative;
}

#main #navigation {
position: absolute;
top: 0;
left: 0;
bottom: 0;
width: 10em; /* or whatever */
}

#main #content {
margin: 0;
margin-left: 10em; /* or whatever width you set for #navigation */
}

html,body {
    height:100%;
}

<main div>
    <content div>
         <navigation div></div>
    </div>
</div>

$(function() {
    function unifyHeights() {
        var maxHeight = 0;
        $('#container').children('#navigation, #content').each(function() {
            var height = $(this).outerHeight();
            // alert(height);
            if ( height > maxHeight ) {
                maxHeight = height;
            }
        });
        $('#navigation, #content').css('height', maxHeight);
    }
    unifyHeights();
});

<div id="container" class="clearfix" style="margin:0 auto;width:950px;background:white url(SOME_REPEATING_PATTERN.png) scroll repeat-y center top;">
    <div id="navigation" style="float:left;width:190px;padding-right:10px;">
        <!-- Navigation -->
    </div>
    <div id="content" style="float:left;width:750px;">
        <!-- Content -->
    </div>
</div>