Highlights of the sessions I've attended have been:
Serious Games Summit - I particularly enjoyed the talk by Straylight Studios discussing their upcoming SalonStar game (I believe this one could very well become a hit with its current target audience...13-18 year old girls), and the talk by Major Jeremy MacDonald of the Canadian Department of National Defense discussing his group's various experiments in making mod's of several different games for prototyping game-based training products.
Allan Murphy's talk on the top 10 CPU and GPU performance challenges. Some subtle stuff going on here ranging from shader patching, slow depth rendering and other rendering related things to load hit store and L2 cache miss.
Lighting with Purpose. This talk discussed some of the fundamental ways a game can use light to immerse the player, including Form (revealing the world), Feel (manipulating the player), Flow (using light to direct travel through both physical and emotional spaces as the game progresses), and Focus (using light to focus the player's attention). Examples were given from Black Rock Studio's PURE.
Pete Isensee's "Beauty of Destruction." Though there were a number of sessions @ GDC this year discussing techniques for physics-based simulation of destructable game worlds, and though you might think I would attend such a session given my interest in physics, this one was in fact a talk about C++ destructors. Good stuff, really good stuff, here. I have learned a lot from Pete's past GDC talks on C++ and this one was no exception. If you write your games in C++, I would recommend you download this presentation when it becomes available (at gdconf.com proceeding section or possibly Pete's own website). Also take a look at his prior talks (linked from his website, http://www.tantalon.com/pete.htm). There's something for all C++ programmers to learn in there. Highly recommended.
Experimental Gameplay Sessions. I never have time to sit for this entire presentation. It always overlaps with something else. But I was able to see the second half. This is always fun. Katamary Damacy was seen here for the first time in America some years ago (and might not have been released in America if it had not been presented here). Same with Rag Doll Kung Fu, Mark Healey's indie release before he and his partners founded media molecule and built LBP. This year, the team that built Sony's "flower" walked us through their game iteration process, and it was a lot of fun to see how they evolved the gameplay mechanisms to achieve a goal of presenting a safe, free game environment that was filled with love, peace, and harmony. (That is how they described their experience goals!) Hazardous Software, Inc., presented for the first time to a large public audience their "achron," a real-time strategy game in which the teams can freely move units back and forth in time (e.g., research advanced weapons in a future time line, then send them back to the past, or move back into the past to change the future after challenger's plan is revealed in the present). Tyler Glaiel presented his "Closure," in which static levels take on dynamic properties by hiding or revealing parts of the level by manipulating lights. Very cool. Kind of reminds me of Echochrome, in that the level structure behaves based on what you can see and cannot see (Echochrome using occlusion and Closure using light to reveal/hide things).
I'll go to the Larrabee sessions tomorrow (at least one of them), and looking forward to that. Intel's graphics hardware offerings in the past have never been spectacularly well received (and I'm thinking not only of the most recent run of integrated chipsets, but all the way back to the i860), but I am rooting for them on Larrabee. An exciting time to be in graphics!