In particular, I found the following papers interesting:
- Efficient sparse voxel octrees: This comes with full source code, so be sure to check it out!
- Stochastic transparency: Very nice use of the MSAA buffer, and pretty nice results. Unfortunately, still a bit slow.
- Light propagation volumes: An updated version of the SIGGRAPH 2009 presentation, this time with blockers and more explanations. Interesting, as this is the first production-ready GI technique I'm aware of (which runs on current generation hardware ...)
- FreePipe: A totally insane amount of work. They've implement a full rendering pipeline in CUDA, be sure to keep this on your radar.
Of course, the other papers were also nice, and I liked the overall high quality. I was in all presentations but one, and I have to say that all of them were interesting and had at least one trick worth noting. The really nice thing about I3D is that it's so small that you can really talk with any author and ask him, something which is not true for SIGGRAPH for instance. Asking the authors is highly recommended to get a real understanding ;)