I am not a fan of the layout of the One Page Checkout module in xcart. I love the functionality and the idea of only one page to checkout.
But that blasted 'apply' button under the customer address section is just missed by all the customers as they go to choose shipping and payment method which is disabled. Then you get customers complaining that they can't checkout.
So after a lot of complaining from my store owners I came up with the solution of only showing the first of the three columns, which forces the user to click a 'next' button. Wording is very important here.
When they click this the next two columns appear below and the page scrolls into position.
There are not too many changes required to implement this and all invlove .tpl and .css files.
Tell me what you think? Here are the sites I have implemented it on
http://www.johnandginger.co.uk/
http://www.beadazzle-boutique.co.uk/
http://www.doggiesolutions.co.uk/