Over time I have turned into a fan of Fred Wilson from Union Square Ventures, relatively famous for investing in Twitter or Foursquare. I like VCs who know what they are talking about. Watch this video, it contains more wisdom on product design than many talks by product guys. Wilson’s 10 principles are:
1. Speed
2. Instant utility
3. Personality
4. Less is more
5. Programmable
6. Personal
7. Restful (meaning anything should have a URL)
8. Discoverable (i.e. SEO)
9. Clean (one could see this as a duplication of 4)
10. Playful
It is also worth listing to the Q & A in the end: The product has to be the marketing vehicle for the product itself.
The 10 Golden Principles of Successful Web Apps from Carsonified on Vimeo.

