rocknbil - 11:49 pm on Mar 22, 2012 (gmt 0)

Most people just use one header.
<?php if (is_page('about')) { ?>
<link rel="stylesheet" type="text/css" href="style-two.css">
<?php } else { ?>
<link rel="stylesheet" type="text/css" href="style-one.css">
<?php } ?>

Or . . you can use is_category or other WP functions . . . or . . .

<?php
// at the head of document . . .
$this_style = (is_page('about'))?'style-two.css':'style-one.css';
?>

<link rel="stylesheet" type="text/css" href="<?php echo $this_style; ?>">

Or . . . using your last choice, create separate templates for the two site versions . . . there's lots of ways to go about it.