Thanks for the replies!
Good to know about the non-VR specific 1070s, will definitely keep that in mind. I want to get a computer ready for the next 4 years of VR (or at least easily upgradeable!).
For the motherboard I am thinking about a MSI Z270 Gaming Pro Carbon (if DP is not really necessary), or MSI Z270 Gaming M5 (if DP is necessary on the motherboard). They both support SLI, have plenty of 3.1 USB ports, and support DDR4.
For CPU I am considering the i5-7600K. A friend told me the Ryzen 5 1600X has been giving some problems, although it seems faster for the same price.
Cooling unit 212 Evo. Power supply, no clue yet. Does it sound reasonable so far?