The below list feature some of the Robust scalable Web 2.0 Drupal powered site which i have delivered so far (taking care of UI and UX & employing agile web practices).

The list goes on as follows in chronological order:

• MNN.com
• Colocube.com 
• Edgecappartners.com
• GCapp.org
• MyGivingPoint.org
• Atlantaeq.com
• CrowdDeal.com
• Cmtagency.com
• Halabol - Initiate the Change
• Indiaenvironment Portal
• Reviewagent
• OSIDays
• Kabbalah.com (Multilingual)

All the sites have been designed & built from the scratch excluding the last. (When I worked on the same)