I've tried creating a rather simple menu, but I have no idea why it won't align to the right. It works aligned left, but it wont' align right.

Here is the entier code from the html test document - any ideas?

Code:
<head>
<meta http-equiv="Content-Type" content="text/html; charset=windows-1255" />
<title>Untitled Document</title>
<style type="text/css">

#menu {
    float: right;
}

#menu ul {
    margin: 0;
    padding: 0;
    list-style: none;
    line-height: normal;
}

#menu li {
    float: right;
    display: block;
}

#menu a {
    float: right;
    height: 25px;
    margin-right: 1px;
    padding: 10px 20px 5px 20px;
    background: #E9EED0;
    text-decoration: none;
    font-size: 1.1em;
    font-weight: bold;
    color: #8C8F7D;
}

#menu a:hover {
    background: #DDE6AB;
    color: #2C2E22;
}

#menu .current_page_item a {
    background: #B8D03B url(images/img01.gif) no-repeat;
    color: #FFFFFF;
}

#upper_nav {
    height: 35px;
    margin: 0 auto;
}

</style>
</head>

<body>

<div id="upper_nav">
<div id="menu">
<ul>
<li><a href="#">first</a></li>
<li><a href="#">second</a></li>
<li><a href="#">third</a></li>
<li><a href="#">fourth</a></li>
</ul>
</div>
</div>
</body>
</html>