OK I figured out the problem. Even though default attrib for the download is marked "default", I figured I could hide the download radio button from tpl_product_info_display.php. Come to find out, removing that code will also make it so that attribute will not select by dafault.

This is the forum post that tipped me off:
http://www.zen-cart.com/forum/showth...t=47987&page=2