Dishonored 2 has piqued my interest more than anything else I've personally seen at E3 so far, but that's mostly because I felt Bethesda did a good job showcasing it -- recapped last year's trailer for a cinematic look, did a cool technical flyby of the art in-engine, did a pretty extended gameplay sequence and concisely explained all the mechanics that were being shown. There's other games I WANT TO BE more excited about that have been shown so far, like Mass Effect Andromeda or several of EA's Star Wars titles, but it was all treated like fluff so far.
That said, also liked the art direction and mood shown in that cinematic trailer for Prey, loved the Doom segment's eagerness to please and seemingly earnest gratitude for being a breakaway hit last month, and just kind of the surprise of a new Quake announcement. I didn't think Bethesda would surprise me quite that much, and while I definitely think it wasn't a mindblowing conference, it felt a lot more genuine and worthwhile to me than EA's earlier this afternoon.