My last PC have died - it was a Shuttle XPC case (to give you an idea of how old - it's an AMD Athlon XP 2200 with a massive 1GB of RAM ) Since then I've had laptops. My current one is a Macbook Pro.
New job soon mean I'm now getting a desktop PC once again.
I've just ordered an Corsair 250D - a mini-ITX case (it's big for a mini-ITX case I know, but it'll take a Corsair H100i cooler and a large GPU too with good cooling)
I also plan on getting a 2nd PC to act as a SteamBox - this will be based in a Silverstone Sugo SG08-Lite case (although I would prefer a version of this without the slot - it won't be getting an optical drive).
The front of the Silverstone Sugo SG08-Lite would look just fine under the TV in the living room, fitting in with all the other consumer media devices. As it only need to drive HD resolution (the TV) the size of the case won't be a problem with whatever GPU I choose for it. It is a SMALL case to work in though so obviously it'll get used with a SFX power supply unit (there's now a 550W unit I believe from Silverstone) and there's their short cables kit as well.