If-then-else logic

I have this logic (see below) in a template that's checking to see if the user entered a value into the $p_pay_through_date parameter.  If it's null, I want to print the current date, otherwise, I print the parameter date.  This works, but is there an easier way to do this with if-then-else logic?  I couldn't find any examples.  PAY_THROUGH_DATE is a form field which is a reformatted version of the parameter $p_pay_through_date.  

<?if:$p_pay_through_date = ‘’?> 9/24/2012<?end if?><?if:$p_pay_through_date !=’’?>PAY_THROUGH_DATE<?end if?>