I am also planning on doing a home build slowly over time by salvaging parts from my old PC and working slowly up. So because I do not know in advance what I will be putting into the case my main concern is flexibility. I will likely start by buying a case, mobo and CPU and then taking parts out of my old Dell to make up the rest. This will get the PC up and working and from there I will upgrade parts on a rolling basis.
I honestly do not care what the case looks like or weighs. These are not concerns, and LEDs and all that fancy stuff is just not interesting. If the case weight a ton and is covered in lights so be it, but if its as light as a feather and plain and boring then thats fine too.
What I mostly want in order of importance is:
Flexibility of future upgrades fitting as many product types as possible, especially huge graphics cards running in parallel.
Cooling Heat sinking properties.
Roomyness inside for future tinkering about, trailing of wires and addition of components.