Serasera gets Tableless

It has been advocated many times that tables shouldn't be use in HTML for layout purposes", and table should be only used for data display. That's why I leaned bit by bit to tableless layout for serasera. Basing myself on what is explained in http://www.w3.org/2002/03/csslayout-howto I tried to create my 3/2 collumns layout for namana.serasera.org
I've tested it on Firefox 1.0.7 and IE 6.0. Comments and suggestions are welcome.
This is the code.

<style type="text/css">
<!--

body    {
text-align: center;
padding: 10px 0 10px 0;
}

*>html body,*>html td,*>html th body.fixedwidth{font-size:11px}

#nav {
    width: 160px;
    float: left;
    margin-left: 5px;
}
#wrapper{
    width: 780px; 
    text-align:left;
}

#content {
    width: 600px; 
    float: right;
    top: 0px;
    margin: 5px;
}

#head {
    clear: both;margin:0;padding:0 0 .5em 0;
}

#leftblock {
    width: 410px; 
    float: left;
    margin: 2,5px;
    padding: 0;
}
#rightblock{
    width: 180px; 
    float: right;
    margin: 2,5px;
    padding: 0;
}
#foot {
    clear: both;
    margin:0px;
    padding:0 0 .5em 0;
}
-->
</style>
<div id="wrapper">
    <div id="head">
    head
    </div>
    <div id="nav">
    nav
    </div>
    <div id="content">
        <div id="leftblock">
        left (or main)
        </div>
        <div id="rightblock">
        right
        </div>
    </div>
    <div id="foot">
    foot
    </div>
</div>