I discovered something today, that NS defines the root containing block as being html whereas IE uses body. That being said, look at this code in both browsers and tell me how you would position the black box so it is in the same location on both browsers - Here is the code:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>

<meta name="GENERATOR" content="Microsoft FrontPage 5.0" />
<meta name="ProgId" content="FrontPage.Editor.Document" />
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252" />
<title>Navigation</title>
<style type="text/css" media="screen">
html{
height:100%;
}
body
{ margin: 0;
padding: 0;
font: 85% arial, hevetica, sans-serif;
text-align: center;
color: #000;
background-color: #00f;
height: 100%;
border: 0px solid red;
}
#container
{
margin: 0px auto;
width: 770px;
height: 100%;
bottom: 0px;
text-align: center;
background-color: #f00;
background-image: url('images/keybg.jpg');
background-repeat: no-repeat;
border: 0px solid red;
layer-background-color:red;
}
#mainnav {
float: left;
width:130px;
height:100%;
vertical-align: middle;
position: relative;
layer-background-colorurple;
background-colorurple;

}
#mainbod {
float: left;
width:640px;
height:100%;
vertical-align: middle;
position: relative;
layer-background-color:aqua;
background-color:aqua;
top:0px;

}
#banner {
float: left;
width:640px;
height:100px;
vertical-align: middle;
position: relative;
layer-background-color:green;
background-color:green;
top:0px;

}
#test{
position:absolute;
layer-background-color:black;
background-color:black;
width:150px;
height:30px;
top:85px;
right:0px;
border:1px solid red;
}


</style>
</head>
<body>
<div id="container" >
<div id="mainnav">
hello
</div>

<div id="mainbod">
<div id="banner">
<div id="test">
</div>
</div>
hello
</div>
</div>
</body>
</html>