GameSpot has posted the entirety of Bungie's GDC talk, given by Joe Staten and Christopher Barrett, about building Destiny's world and characters, over in their YouTube channel. Honestly, stuff like this-- showing the depth and breadth of thought that Bungie puts into making its worlds-- gets me a lot more excited about the game than trailers.

Bungie also has embedded a version of the talk over on their own site, but it's a Flash-only player that probably won't work on most mobile devices.