Betsy, as she is affectionately known, was the end result of a many year build up to completion. She was my first fully custom PC, having previously been performing Dr. Frankenstein-esque manipulation of the computer I purchased when I was 14 in order to keep it shambling forward. Finally I gave up on my HP Pavilion-based monstrosity and it's dual core E8400, and began this first of projects. The case I had acquired some years ago to migrate my first PC into, as the case it came in didn't have enough room for a full sized graphics card. Sturdy case with reliable build quality, and was thus my base. I sprung for the x4 860k instead of the beloved G3258 for simple reasons. First, it's slightly cheaper. Second, I wanted a quad core instead of a dual core, even if in the end they perform about exactly the same.
The memory was chosen because I liked the way it looked. A black heat spreader with a low profile, and good volumes. I know it's usually not recommended to go with a number of sticks that isn't 2x (20=1, 21=2, 22=4, etc), however 8gb wasn't enough at times and 16 was far too much. I had no stability issues, it was pretty cheap ram, and it worked just fine.
The SSD happened to be the only one I could purchase locally. It was a big upgrade compared to my HDD I'd been using previously for my boot drive, and I can honestly say I will never have a computer ever again without an SSD in it. The HDD from the old computer was carried over for mass storage, as it still worked just fine and didn't have the worst read/write speeds in the world.
The R9 270x was purchased used off of craigslist. My last system had an AMD 5870 in it. at only $80, it was very cheap. Didn't have any issues with it.
Power supply was on sale at the time of purchase, and had sufficient power for everything. Didn't seem to have too many negative reviews, and it worked fine. Only real complaint was that it is ugly. Like, real ugly.