If you have a need now... Build now.
If you wait for the next best thing, you will wait forever.
If you need a budget build, kaby lake and the HD630 graphics will get you started.
That lets you better evaluate how strong you need for graphics.
If you have a need for batch apps that can run many threads, it is hard to beat ryzen at many price points.
The coffee lake processors will likely be priced competitively, but so far, there looks to be no answer to the massive threadripper for such apps.
If your need is for gaming, kaby lake and ryzen have suitably fast single thread performance in mid range builds.
It is only when paired with a GTX1080ti card that one can use the 5.0 clock of I7-7700K.