Hi guys! Hoping for some feedback please - I am finally upgrading my 10 year old pc build, and need something that will keep going for at least a couple of years - my current PC has had its day, and while it has survived longer than anticipated, it is slow, can't keep up with my work requirements, PC temps are higher than they should be, I struggle playing any games on even the lowest settings, and the motherboard has failing ports (thanks to load-shedding/power surges over the years, before I had a surge protector). Would really appreciate some advice on price expectations and if I'm on the right track for the build 
Thank you in advance!
Background:
- I'm not a huge gamer, so not looking to play the latest releases on the highest settings with the best FPSs - just the occassional game on moderate graphics settings on my dual display 720p and 1080p monitors is perfect (my current specs do not support this however).
- I do some graphics design work on occassion.
- My PC also serves as my plex media server for the family (typically up to 3 devices streaming simultaneously).
- In addition to this, my daily workflow typically consists of at least 20-40 chrome tabs running simultaneously, along with a full MS Office Suite, and my work-software.
- When I travel, I often need to screen mirror and pull confidential files off my PC.
- Long-lasting, fast, and reliable hardware is important.
- I would love the convenience of built-in wifi (for my 100mbps fibre line), to free me from extra lan cables.
- A cool, quiet PC would be great, with as much dust-resistance as possible. I don't have the time to open up my chassis every month to remove mounds of dustbunnies.
Current PC Specs (To Be Replaced):
- Chassis: Coolermaster CM690
- Motherboard: Asus P6X58D Premium LGA1366
- Processor: Intel QuadCore I7-950 (Bloomfield Nehalem)
- CPU Cooler: Coolermaster V10
- Memory: 12GB DDR3 Memory at 1066MHz
- 1 x 8GB DDR3 Memory at 1066MHz
- 2 x 2GB DDR3 Memory at 1066MHz
- Storage:
- 1 Samsung Evo 840 SSD = 240GB
- 3 WD HDDs = 6TB
- GPU: Nvidia GTS-250 Stock
- PSU: Aerocool V12XT-800
- Peripherals:
- 2 x 1080p monitors
- Logitech MX performance mouse/keyboard
- TPLink wireless access card for wifi (this is ancient - had to play around with compatible drivers to get it to work)
Potential PC Specs (Reasonable? Overkill? Not enough? Please share your thoughts)
- Chassis: Corsair Obsidian Series 500D / CoolerMaster Cosmos II (something with good airflow, easy to build in, easy to clean, expandable, and long-lasting: room for upgrades/new builds etc)
- Motherboard: Asus ROG Maximus XI Hero WIFI (is this worthwhile? Wifi reasonable/effective? Meets my needs?)
- Processor: Intel Core i9 9900k
- CPU Cooler: Unsure? I've heard of the H115i cooler?
- Memory: A reliable 16GB? 32GB? of DDR4 at around 3200MHz
- GPU: Something relatively inexpensive that can handle the basis, like the Gigabyte Radeon RX580 8GB? Perhaps a little better?
- PSU: I imagine my current 800W PSU should hold up, but am open to replacing if needed. It's age and bronze rating is invariably quite energy-inefficient
- Storage: Depending on how much everything costs, I might consider buying a larger primary SSD (my current SSD is running fine though)
Thank you in advance!

