Not turning it into a fight, just expressing my opinion. Not forcing it on you either.

Also Xii and Pimath if you don't like GrUB as your boot menu just use rEFInd. It's easily customizable and themable. A lot easier than GrUB.

No, I don't care about the bootloader. I'm just saying it's a pain to dual boot Win8 (UEFI-only) and Ubuntu (EFI-only).

Trackmania on full graphic settings without any lag at all
EDIT: and building AUR stuff is suddenly so fast

That messy wiring. You could make it cleaner, it will improve airflow and help the PC cool better. Like so :

All the cables are behind the panel on which the motherboard is attached. Well, it's true I could make the bottom better but it's not a big deal since there's few cables hanging out in there.

Edit Sorunome: resized image

What I don't get though is that you guys need so much space for a computer, here's my setup so  you know what I mean:

WARNING! 4K pictures!

The case is a Antec Aria, A microATX case, which is 10.6" x 7.9" x 13.2" (WxHxD).
It normally comes with a PSU that was build for it, but the guy I bought it from blew that thing up.

So instead I took my own PSU and just put it on the spot where normally the CD Drive and the HDD's were going to go.
The HDD's not lay under the card reader where normally a USB hub is attached, that one is my own and was routed to the back.

As far as specs go, it can't compete with your PC's. This was a budget build and it was in total ~120 euros.

CPU: Intel Pentium D, dual core rated @3 ghz. (Socket 775, still very much upgradable)
RAM: 2GB DDR2 memory (I can upgrade this to 4GB If I wanted)
PSU: Some PSU that gives 350watts.
GPU: GeForce 9500GT, overclocked to the maximum stable.
CD Drive: None
USB Ports: 4
Sound Card: None
Cooling: By PSU, CPU and a external one which is placed all the way in the back. Its not perfect, but it does the job.
Over time it gets hotter and hotter, but this takes a long time; after about 10 hours of maximum load (Yeah) it was 70 degrees.
If I think it gets to hot I just temporarely take the top off and it cools quickly.

Edit Sorunome: resized images

What I don't get though is that you guys need so much space for a computer, here's my setup so  you know what I mean:

As far as specs go, it can't compete with your PC's. This was a budget build and it was in total ~120 euros.

Well you said it yourself, we have big PCs for big performance. And if you don't need big performance indeed, you don't need a big PC.
That's why I have two laptops, one that runs AC IV and Project M, and one that barely runs Lubuntu to work wherever I want.

As far as performance goes for me; It runs everything I want and it runs it smoothly.
So thats things like Minecraft or League of Legends, such games play at about 40-100 fps at medium to high settings.
Other than that I just browse with it, play music and program on it, although I prefer programming on my laptop.

And yeah, cooling it can be a real nightmare, especially if your video card came without its own cooler .-.