[philrisk]

Actually some things not right as $main ne 'product' should make it not appear on the product page. I know its not the best way of doing it but this is how I have mine:
{if ($main neq 'cart' or $cart_empty) and $main neq 'checkout'}
{if $main neq 'product'}
{if $main neq 'authentication'}
{if $main neq 'giftcert'}
{if $main neq 'help'}
{if $main neq 'register'}
{if $main neq 'pages'}
{if $main neq 'wordpress'}
{if $main neq 'order_message'}
{if $main neq 'address_book'}
{if $main neq 'orders'}
{if $main neq 'customer_bonuses'}
{if $main neq 'wishlist'}
{if $main neq 'error_ccprocessor_error'}
{if $main neq '403'}
{if $main neq 'survey'}
{if $main neq 'surveys'}
{if $cat neq '0'}
{if $manufacturerid neq '0'}

left bar.tpl

followed by an equal amount of {/if}s