I was using my Raspberry Pi for quite some time as a file server for backups, git repo, torrenting and media sharing. I was getting bored of the speeds, so in summary of my change I've gone from 1-2MB/s to ~12MB/s. I'm very pleased that there is no more bottlenecks and I can pleasantly stream, remotely and locally, whatever I want.
My cabling is messy, however sufficient air flow travels through the middle of the case and out to the exhaust perfectly. All the cables are only messy down the side, where there is no requirement for a clear pathway. When I stick another (or few) hard drives in there, I will have to sort it out. However, for now with just two drives installed on one side, it's perfect. I'm only using one of the front fans as a result of this.
The case: I went with this one for obvious reasons. It is really popular among ITX builds, due to its elegant and simple look. It's a very solid build and does not feel cheap at all. I've seen people moan about the power button, but I see no issue with it. I only referred to the manual it for the PSU, but it provided a huge amount of ambiguity. The case itself is very quiet, on low settings you can hardly hear it from over ~1m away. Even low settings keeps the CPU @ ~25c.
The CPU: I was originally going to have the i3 4130, but I'm so glad I didn't and I chose this one. Not only price, but performance. I think in further hindsight, the AMD A6 6400 and the ASRock FM2A78M-ITX+ would have been a far better deal because the Intel currently in there is definitely overpowered for what it's currently being used for. Although, when I graduate it will leave extra power for when I want to take my home networking more serious.
The mobo: the cheapest 6x SATAIII and USB 3.0 mobo out there, and just so happens to be very popular. So this one was a no brainer. Its BIOS is feature rich with a nice UI. It also comes with a RAID controller, which I'm dubious of using as a friend of mine warned me of the "write hole", so that will be a nice learning curve I'm sure.
Storage: The SSD was such an impulse buy when I walked into Novatech. I keep this in my room you see, and I hated the noise of spinning disks with the Raspberry Pi whilst I was in bed. So I thought I'd get an SSD too :-P oh and the HDD came from my PC, as that also has an SSD in it too.
The RAM: cheap and cheerful. I'm only running Ubuntu Server with no DE, so after my packages are installed I'm left with ~900-700MB. I will upgrade in due course when I need to.
PSU: Cheapest semi modular, of the lowest wattage, that was also very popular. This PSU is very quiet. I was tempted to fork out for fanless, but I'm glad I didn't because I really cannot hear this.
I don't really know what else to write...