Feature list

Setup & Architecture

Free open-source PHP/MySQL solution
Can work as a standalone online store and in connection with Drupal CMS with tons of ready-made Drupal modules
Web-based installation wizard that installs both LiteCommerce and Drupal (when run from the Ecommerce CMS package)
Storefront sections and blocks can be managed in the Drupal user interface
Modern object-oriented MVC architecture
Flexible modular system allows customizing without hacks to core files and simplifies upgrades
HTTPS/SSL support
Fully customizable design & layout
Compatible with popular browsers:
IE 7+, Firefox 3+, Chrome 8+, Safari 4+, Opera 10+
Using ORM technique (Doctrine 2)

Custom search engine friendly URLs (when connected to Drupal)
Custom META tags for products, categories and other website pages (when connected to Drupal)
OpenGraph meta tags used when sharing product pages in Facebook, Google+ or other social network
Featured products, Bestsellers, New arrivals and Coming soon blocks promoting products in your shop
Market price
Who bought/viewed this product also buy
Recently viewed
Products on sale
Discounts depending on the order total (volume discounts)
Wholesale pricing
Discount coupons

Storefront sections and blocks transparently integrate with Drupal pages into a single ecommerce website
Catalog pages are updated via AJAX without page reloading
Fast AJAX store-front interface
Full drag-and-drop support
Products quick look
Image galleries with a popup image browser and an in-page zoom function
Facebook comments tab
Mouse wheel updates product quantities
Fast one-page checkout (working for anonimous customers as well