Googling for "Drupal E-commerce" brings up a ton of old results, and I wanted to weed out all the garbage. I'm a regular on SO but I thought that I might get better insight/advice here.
Running Drupal 7.9 (multiple sites will be installed but running their own Drupal install), what e-commerce packages should I install (shopping cart and payment options)?
What are the pitfalls to look out for?
What theme do you suggest, that is geared towards E-commerce?