Here's the latest in my line of templates for 2.3.3.4 which I've called "Kripke"…
Header Area
I've included the breadcrumb in the header area and also a "logged in" message which has been something under discussion in the official osCommerce forum;
Main Content Area
I have recoded the "new products" and categories "products listing" module from scratch to utilise a more semantically correct "list" of products, example.
In the product page, I have removed the "bx gallery" in favour of a custom coded gallery which gives better results in my opinion (example; you can click on the main image or any of the thumbnails).
Footer Area
Contains a nice looking "social" and "payment" box as well as information, contact details and so on.
Other bits and pieces
Index page has a slider system of images (that fade in and out), which is controlled by the usual Banner Manager system. I've also made some changes in the categories box to output a line between each category and some arrow icons in each box. Shopping cart box in the header is interactive, showing buttons when a checkout is available.