Building replacement for iMac27

[cyberalien]

I've been a iMac user for over 10 years, however after 3 iMacs I've decided to switch back to PC world. So I'm building a rig that would be better than my old iMac27, that would be great for designing, occasional gaming and would last for many years.

My current choice of components:

PCPartPicker part list / Price breakdown by merchant

CPU: *Intel - Core i5-8600K 3.6GHz 6-Core Processor ($268.95 @ Amazon)
CPU Cooler: *Deepcool - GAMMAXX GT 29.5 CFM CPU Cooler ($44.99 @ B&H)
Motherboard: *Asus - Prime Z370-A ATX LGA1151 Motherboard ($154.99 @ Newegg)
Memory: Corsair - Vengeance LPX 16GB (2 x 8GB) DDR4-3466 Memory ($229.99 @ Amazon)
Storage: Crucial - MX300 525GB M.2-2280 Solid State Drive ($139.99 @ Amazon)
Storage: Seagate - Barracuda 2TB 3.5" 7200RPM Internal Hard Drive ($54.99 @ Amazon)
Video Card: *Asus - GeForce GTX 1070 Ti 8GB ROG STRIX Video Card ($524.89 @ B&H)
Monitor: Dell - UP2716D 27.0" 2560x1440 60Hz Monitor ($524.99 @ Amazon)
Total: $1943.78

I have few questions that might seem silly:

1. What case should I pick? I'm very confused by large selection. I don't want any lighting and fancy stuff, just simple elegant case.

2. As I understand selected motherboard has place for K2 SSD built in. Can I also add regular HDD?

3. Is built in sound card in Asus - Prime Z370-A any good or should I pick a separate sound card?

 

[cyberalien]

Solved. Found everything I wanted in other posts on this forum and some youtube reviews.