So I shall estimate that 500GB is enough for Windows, your tools (Blender + other installed programs) and the current project. To store these 500GB to which you would want quick access, I recommend the Samsung 960 Pro 500GB for 290USD. Why this SSD?
- It is the fastest somewhat affordable SSD, meaning you will get GB/s transfer rates from it, which will make even large projects load instantly.
- It is a Samsung Pro series SSD, meaning it is meant to survive more write operations (which will probably happen)
- Samsung is a very reputable brand when it comes to SSD and this one is covered by a 400TBW / 5yr warranty, meaning if you write less than 220GB per day on average on your SSD, it will last you for at least five years, if not much longer, speaking for its build quality.
Now of course 500GB won't cut it if you want to archive old projects. So after you are done with your current project you'll have to move the data to your WD Black 4TB HDD for 186USD. On this drive you have essentially 4000GB of storage available, which should be plenty for a couple of old projects. But what does the "Black" mean? It's the WD series of HDDs "for gamers" featuring technology that is supposed to make the HDD faster, however the really nice side-effect of this is that these technologies treat the mechanical disks inside nicer meaning the HDD will last longer than an average HDD (and WD also gives a 5yr warranty). For further reading I recommend this guide on WD drives.