A lot of these upcoming games look cool but out of everything I have seen from E3 so far this is the one that has me the most excited at the moment.
Outside of that, I'm also looking forward to Halo, Far Cry 4, The Division, and The Order. I think Evolve and Rainbow Six look really cool too but those games both look like they require heavy cooperation. I will try both of them but I don't see either game being something my friends would be into and playing that type of game with strangers is hit or miss. I did love the Left 4 Dead games when I got matched with a good team. I easily put 100 hours into that series but getting matched with the wrong people completely ruins the fun.
Edit: if you don't want to watch the CG opening the gameplay starts about 2:20 into the video.