Hi,
 
Regarding to install video card or not, depends on a few issues. Basically for DAW only use, if the motherboard / chipset supports built in graphic, video card is not required.
 
Z170 platform supports build in graphic, so there is not need to get a video card.
 
https://www.asus.com/us/Motherboards/Z170-A/specifications/               (check the graphic section)
 
For example, my older board, an Intel DP67BG does not have built in graphic :
 
http://ark.intel.com/products/50244/Intel-Desktop-Board-DP67BG
 
And for my system above, I get the lowest spec fan less graphic card, just to enable display. It also depends if you want to drive more than one display. Z170 by default supports up to 3 full HD monitors, so it should be enough by itself.
 
Regarding 6700 vs 6700K, K series CPUs are meant for overclocking. If you don't intend to overclock, 6700 will do and it's cheaper. For me, I prefer the K series even though I do not overclock .. having the thought of one day I might just need to over clock it a bit when future OS / Sonar need more power..  (but very unlikely I'll overclock the CPU full time, but I do have the option to experiment).
 

Thanks to everyone who commented here and a huge thanks to Wookiee for his advice. As you can see from my signature I took the plunge at last and all is going well - even after the new Windows 10 update.

groverken
Thanks to everyone who commented here and a huge thanks to Wookiee for his advice. As you can see from my signature I took the plunge at last and all is going well - even after the new Windows 10 update.

 
Congrats Groverken!! Looks to be a very nice system.

Next stop fro you is The Song's Forum to post a song! 

I must say that the whir and hum of 5 case fans, 2 video card fans, the cpu fan and 2 external cabinet fans have a hypnotic and lulling affect giving a sense of well being and unity with my environment. :)
 
For some reason, recording in the same room doesn't impart the same harmony. Go figure...