Paper Garden Projects is a fully responsive, WordPress site with e-commerce features. Because the subject matter was paper craft and card making, we worked closely with the store owner and blogger Catherine St. Clair to convey a "hand-made" feel. We used shadows and textures along with her original hand made art.
On the technology side of things, we managed to get a fully responsive experience with only 300 lines of custom code. This is due, in no small part, to creating a child theme of the excellent Twenty Twelve theme. Plugins used include Query Wrangler that gave us a lightweight query builder interface similar to Drupal's Views module. Easy Digital Downloads basically provided the entire store in one plugin module. We also integrated Google Analytics and a jQuery scroller very easily.
Additional, we found some of the digital downloads could be quite large, weighing in at over 300 megabytes. We decided to integrate the store with Amazon S3 for the delivery of the digital product.