There's nothing wrong with building a good rig to last for a few...

There's nothing wrong with building a good rig to last for a few good years at-least. Some around here might even call that an investment .

If you can afford it, then yes you cant go wrong with an i7.
For GPU depends on what resolution, if you aren't too concerned with the price(or can write it off on tax), then definitely go for a 4k setup(see above).
I would recommend also at-least 32gig ram (can do 64gig on the 1151 board), an SSD for the OS and a standalone backup NAS that you only connect to the network when you wish to perform a backup. Your files are important and I don't trust cloud services to back mine up(internet isn't fast enough anyway). Using RAID arrays does not protect you from viruses and file corruption so I don't bother

This is going a bit full on nerd but a good UPS (uninterruptible power supply) is good for outages and as @Freehold said, a laptop or a backup system itself is highly recommended, including a wireless internet carrier and surge protection of-course.

Regarding backup internet also, Telstra https://www.telstra.com.au/small-business/bundles#dotnbn has a wireless backup in-case of landline outages. You're boned though if the whole network goes down of course .

Overall will cost you a pretty penny but damn well worth it.