Here are some highly customizable, good looking and easy to use drupal themes for ecommerce websites.
inStock is a responsive theme that is built with Bootstrap framework and uses Drupal Commerce for its ecommerce functionality. It includes a lot of features and you can get 99% of the site ready in just a few minutes.
ShopFine is modern and clean Drupal Commerce Theme based on Bootstrap framework, and it comes with a preconfigured profile. Its an out-of-the-box theme which can get your site ready with just a few clicks.
Expressa is a fully responsive theme built using Twitter Bootstrap framework and font awesome icons. It also comes with both the full demo install or just the standalone theme if you want to use it on your existing site.
Marvel is a fully responsive theme that uses Bootstrap 3 framework and provides 7 types of home pages, 5 different header styles and 4 types of shop page layouts to choose from.
TB Metroz is a Drupal commerce theme with a clean and modern look.
Theme has 6 skins to choose from