Role dependant CSS classes

Need different CSS for subscribers and visitors, maybe other roles down the line.
Assume it's PHP...maybe something like this(dunno what should go in the brackets):

<?php
global $current_user;
get_currentuserinfo();
if ( user_can( $current_user, "subscriber" ) ){

// WHAT GOES HERE?

}
?>

Or define a new class?

Thanks!