Source: Beyond Agile: the Studio Model
Michele Einhorn, in her blog article, 12 Principles of Agile Methodology, laid out a quick summary of the Agile principles, something worth going back to in this kind of discussion (she includes more details under this, but in the interest of brevity, I'm just giving the bullet points themselves.
1. Satisfy the Customer 2. Welcome Change 3. Deliver Frequently 4. Work Together 5. Build Projects 6. Face-To-Face Time 7. Measure of Progress 8. Sustainable Development 9. Continuous Attention 10. Keep It Simple 11. Organized Teams 12. Reflect for Effectiveness