because I keep telling myself it is a temporary case anyway and that I will get a new one soon, for 2 years.
Get a really good case. If you have space and don't move often, get a massive full tower and build new parts into it one-by-one.
I started doing this a decade ago and I am certain that every single component in my computer has been replaced at least once, most 2-3 times or more. About every 3 years, when the motherboard is due, I completely dis-assemble it and clean it thoroughly.
With this method, upgrade costs can be contained in the $50-$200 range (per instance) and you can stay up to date painlessly.
I am to the point where I would love to get a new case (mine has half a dozen fans, but all are 80mm, and the USB and audio sockets are on the top rather than the front (it was a "server" model I suppose)) but I am still waiting for just the right one.