Magento Beginner's Guide
It might be a shameless plug, but Satchmo - http://www.satchmoproject.com is a completely open source option. It's not perfect (what software is) but I believe it is a much better alternative than most of the PHP based alternatives.
I am one of the core devs so I am biased but do feel compelled to chime in with an alternative to the PHP based solutions out there like Magento.
Practical Django Projects
Well, take a look here - http://www.djangosites.org/ to see just a few sites developed in Django. Django itself is the killer app. It's a framework.
I'll shamelessly plug Satchmo - http://www.satchmoproject.com as a successful online ecommerce/shopping cart that compares very favorably to the PHP based ones.