I also built a PC with a Skylake (i7 6700) CPU (ordered parts around Dec. 10 2016). When I ordered the parts I knew that Kaby Lake was coming out in January but I wasn't interested in the changes the Z270 chipset brings to the table. Perhaps the most interesting one is Intel "Optane Technology" but it's not even out yet.
@Mom, don't worry, you still have a fine CPU.
Z170 vs Z270:
https://www.pugetsystems.com/labs/articles/Z270-vs-Z170-What-is-the-Difference-877/