At GeForce LAN 6, DICE's senior software architect Johan Andersson gave a fantastic talk about the technical aspects of the graphics renderer in DICE's Frostbite 2 engine, which is the engine being used to power the recently launched Battlefield 3. Short of a GDC session it's one of the most comprehensive graphics tech talks we've seen in recent years, and definitely one of the most accessible. While the talk was public, the official recording of it was withheld until today to promote the release of Battlefield 3.
It has since been posted in 5 parts on YouTube, each covering a different aspect of the engine: objects, lighting, effects, terrain, and post-processing. If you have an hour and an interest in game engines I'd highly recommend taking the time to watch all 5 parts - it's an extremely enlightening view on how Frostbite 2 works, and a good insight into how similar DX10+ engines will be built in the future.
Frostbite 2 Graphics Tech Talk Part 1: Intro & Objects
Frostbite 2 Graphics Tech Talk Part 2: Lighting
Frostbite 2 Graphics Tech Talk Part 3: Effects
Frostbite 2 Graphics Tech Talk Part 4: Terrain
Frostbite 2 Graphics Tech Talk Part 5: Post-Processing & Conclusion