(Edit 26/09/2013: New photos of cable management. Not beautiful, but infinitely better than what it was before.)
I benefited from reading other completed builds, so I thought it only fair that I contribute myself...
My Xbox 360 is reaching the end of its life; purchased from launch, its been repaired 3 times and is now struggling to read disks, the fans sound like a hairdryer, the wireless adapter refuses to maintain a connection longer than 30 seconds, and some save-files have become corrupted. Coincidentally, my friend introduced me to the Steam summer sale and the games have been struggling on my laptop, so I decided upon building myself a budget gaming PC.
CPU: 3.4GHz quad-core processor for a decent price Memory: To save a bit of money, I chose 4GB rather than 8GB. Storage: I'm using a spare 120GB 2.5" HDD to install games and programs on. The boot time from the SSD is crazy: about 6 seconds! The 120GB is full and I haven't installed everything, so I shall have to upgrade that in the future. Video Card: I get pretty decent performance off games at high-preset. Averages 46FPS on BF3 and is beautifully smooth on Burnout Paradise, very rarely dropping below 60FPS. Power supply: Browsing the forums, it was clear that to skimp on the PSU is to court danger, so I chose Corsair as they seem to be a reliable and trusted brand. OS: I could have saved a little by choosing 7, but I quite like the Metro Start screen of 8.
Took about 3 hours to build (disregarding the the month worth of evenings watching video tutorials and researching parts), although Amazon delivered the SSD and memory the following day despite it being in the same order, so I had to wait for those before I could install Windows. I was impatient to see it work, so I turned it on without any RAM; the motherboard speaker just gave 3 beeps rather than showering sparks and bursting into an expensive flame, which was comforting. Coming from the perspective of a complete novice, the case was really easy to use. The cable-management's great, but the power cable was too thick to hide in the crevice. I didn't realise that a processor has a fair weight to it, so I nearly dropped it taking it out of the box. I was genuinely worried that I would bend the pins installing it after reading some horror-stories, but it went in without fuss. Also, the wireless adapter software doesn't install on Windows 8, but it works nonetheless. I'm fairly sure my Dad thinks that I have OCD from the amount of times I was touching the case and my metal lamp whilst building.
Thought these links might help some fellow first-time builders...
How to install an AMD CPU http://youtu.be/SdyWDOf19J8
Compare GPU performance http://gpuboss.com/
Newegg TV How To Build A Computer Series http://youtu.be/lPIXAtNGGCw I can't praise this series highly enough! Loads of info but explained in simple terms and really clear demonstrations.
Lifehacker How to Build a Computer from Scratch http://lifehacker.com/5828747/how-to-build-a-computer-from-scratch-the-complete-guide
Logical Increments (Like a cheatsheet of PC parts) http://www.logicalincrements.com/
(Also shout-out to PC Part Picker, this site is incredible!)
Anywho, sorry that was far too long. But to anyone considering building their first PC, it's not as horrific as I imagine you worry it will be.