We're a small children's theatre company and make great use of Google Analytics. We use CiviCRM/CiviEvent for our patron database and online ticket sales, and wanted to add Google Analytics ecommerce tracking to track the effectiveness of our various marketing activities.
I did this by copying /civicrm/templates/CRM/Price/Page/LineItem.tpl into a custom template directory, and adding the tracking code to my custom version. All of our "events" use price sets, and the price options are various ticket categories (child, adult, senior, etc). The code below tracks not only the entire order amount, but also the quantities of individual items in the order.