How much porn you store is what really increases the need for storage!!
Ummm these days... $3k ...
Breakup will be roughy:
Video Card - $1k
Monitor - $800(ish)
Remainder - Parts
IJK, JW, ARC or MWAVE are my "go to" places in Sydney these days, and if you can put it together yourself you can save some coin.
Anyway... lets see what we can do...
BE VERY careful with Intel 8xxx series CPUS and LGA1151 motherboards. Intel in their infinite wisdom decided to make the CPUs physically fit in older LGA1151 boards, but he new Coffee Lake CPUs are pinned differently. So anything that is LGA1151 with a Z270 chipset, may NOT work. Z370 is the chipset designed to work with all new Intel 8 Series CPUs.
That futureproofs you a bit.
The Coolermaster Masterbox is a friggin cracker of a case for the money spent. Huge amounts of room the tempered glass looks amazing, and cooling is fantastic. I use one for my test lab server.
Main rig is a Corsair Obsidian 650D.
XPPC is a Lian Li
TestlabWS is an Antec 300.
I've stuck to MSI/Corsair gear because it's bloody well built and reliable. I've ignored Intel Optane memory as it's not worth it with an SSD.
That motherboard has a second M2 SSD slot for later expansion too.
I've deduced $149 per Western Digital RED drive but if you are storing data I'd recommend 2 of them in RAID 1.
NOTE: That is BEFORE the monitor price. Monitors are VERY subjective. Do you want curved/non curved? Ultrawide or standard? 1080p/2K/4K? Freesync or not (with Nvidia cards not an issue)?, 144Hz or not?
Stick with AOC or Samsung brandwise.
For my racing sim I use this AOC:
https://arc.com.au/product/59620 which is $469.
For my main setup (that I surf Kennel on and use everday) I use 2 x Samsung 24" S24D590L thin bezel Monitors. Love them.
For my testlab PCs (2) I use an AOC 27" basic monitor with VGA/DVI/DisplayPort/HDMI outputs so I can have 2 PCS and my laptop hooked into it.