What packages will stop supporting 2.7 Don't panic, ArcMap will still be using it... at least for 10.7
Numpy/Scipy drops support of python 2.7 Dec 31, 2018 get your code ready
Guido speaks 2020 is the big end The BDFL, Guido speaks at PyCon 2016 about python 2.7
Announcement Overview — Python 3.7.0a0 documentation yes... 3.7 is on its way
Announcement What’s New In Python 3.6 — Python 3.6.0b2 documentation final release candidate
iPad and iThings Python 3.5 comes to iThings don't get further behind...
Additional The key differences between python 2 and 3
Some frivolity ... but some resources
do check the resources section.