The 10 year of Dieselgate is interesting just from a "how bad is it really?" PoV, I saw the part about curves and other defeat devices already [1].
The Rowhammer talk is likely going to be great as well, I like Daniel's work [2].
The practical Cross-VM Spectre was interesting to show this is still a problem [3].
The opensource secure element was good for trying such a thing, but I wasn't that impressed with the content [4].
[1] https://cfp.cccv.de/39c3/talk/7MSRA7/ https://media.ccc.de/v/39c3-10-years-of-dieselgate
[2] https://cfp.cccv.de/39c3/talk/3JXAJJ/ https://media.ccc.de/v/39c3-rowhammer-in-the-wild-large-scal...
[3] https://cfp.cccv.de/39c3/talk/ATYLN9/ https://media.ccc.de/v/39c3-spectre-in-the-real-world-leakin...
[4] https://cfp.cccv.de/39c3/talk/9DYZXG/ https://media.ccc.de/v/39c3-lessons-from-building-an-open-ar...