answer:Dust free and well-ventilated are hard to combine unless you want an enclosure with many air filters and the maintenance that that entails. And if you need access to anything internal like putting a CD/DVD into a drive, or a card into a reader then you can forget it. I suppose you could go with external optical drives and a card reader, but those components would still be vulnerable. If you want efficient CPU air-cooling, you will need to duct the CPU fan to such air directly from the exterior as opposed to circulate preheated air inside the case, but it sounds like you are leaning towards liquid cooling. Water cooling is your best option to keep your case clean, but then you’ll have to clean radiators. Trust me, that is no fun, and no easier than cleaning the CPU heatsink on an air-cooled system, though it is easier than cleaning the heatsink on most graphics cards. In the end, you will have a dusty mess somewhere though. You will also need to move the power supply out of the case unless you want to build your own. They all have at least one fan, often two, and require a lot of air to move through them; enough that air filters will hurt the cooling more than a little dust could. And no, you can’t water-cool your PSU… unless you build a custom one. Now, I work in a steel mill and there is enough dust and crap in the air sometimes to make visitors hack up a lung, so you think that the computer workstations we use for production tracking (normal PCs with no filters) would be pretty nasty inside, right? Nope! It surprised me a little too, especially the one near the sandblasting booth, right next to the debur station (enough metal dust that a paper facemask is recommended), but if those computers can run for years under those conditions then maybe you are overestimating the dangers of a bit of dust. You also seem to be overestimating the dangers posed by a couple of half-second blasts of compressed air every month or three. The less often you do that though, the harder it is to clean when you finally do do it, and the more invasive those cleaning methods are with the resulrong increased risk of damage. By the same token, it’s a little bit of a hassle to change your oil every three months compared to never changing it at all, but multiple oil changes are less of a hassle than an engine rebuild/replacement. Keeping a clean-room environment is more expensive and maintenance intensive than just proper housekeeping. Fortunately, making a badass-looking case is fairly easy.