I haven't gamed in years and wanted to get back to it. Didn't want to play the newest games (e.g. BF4) but wanted to have a powerful enough PC that could handle it at 1080p high settings if I wanted to get into them later. Also thought about getting a PS4 awhile ago and loved the look of next gen consoles. Decided not to, due to the limitations with a console, but wanted the SFF and low price. $600 was my target, and I got to just a few dollars under it.
CPU (i3 4130)
I built this PC for gaming exclusively so did not need a strong CPU. Being under a budget I found the i3 to be ideal combination of price and performance. So far very happy with the performance and no issues.
CPU Cooler (stock)
Before cable management and turning up the CPU fan to full speed in BIOS, my CPU would hit a max temp of 70C+ while gaming. Now it is at 59C max during gaming, which I consider quite good considering it is only stock. It was easy to install, although I made a mistake and had to re-set it. The temps look good so not too worried about that. My plan is to use this for awhile and upgrade later if necessary. My only problem with it is the fan. It is incredibly loud. When stopping the fan with my finger, my PC is almost silent, so I'm sure it's the CPU fan. With the SG05's small height and PSU placement, good choices are limited so I'll be sure to do research on compatibility.
Mother Board (ASRock H81 ITX)
This was one of the cheapest boards I could find at this size for Intel. The bad: no USB 3.0 headers, no PCI-3.0, no wifi. Although at $59 it's tough to beat (it dropped to $44 a few days after I bought it). BIOS was easy to use even for beginners like me and no issues yet. The BIOS lan driver utility was nice in theory but it kept on disconnecting on me. I had to download all the drivers on another computer and install via USB. The only thing was I opened it up when I was on carpet so hope I didn't mess it up with static.
Memory & Storage (G.Skill, WD Blue)
Not much to discuss here. Found the on-sale item, checked it was compatible with the ASRock motherboard and got it. The only downside is that there are the huge heat spreaders on top of these, and may cause some incompatability should I want to upgrade the stock Intel CPU cooler later. Didn't want to go with SSD since this was a budget build. No problems yet with the HD.
Graphics Card (MSI R9 270)
It was between the R9 270 and the GTX 760. Saw that the MSI R9 270 dropped from $200+ to $178 (close to MSRP). Also really liked how the MSI cooler looked. I was concerned that the 10.08'' long MSI was going to not fit, since Silverstone stated that only a 10'' would fit. It was difficult getting it in there (felt like a puzzle game) and there was probably a 0.1'' clearance left. So technically it could probably fit a 10.2'' GPU.
So far I'm playing everything I have on Ultra at 1080p and very happy. Based on benchmarks, this card should be able to handle all the new games at high or very high at 1080p with limited AA. The GTX 660 is probably the R9 270's direct competitor, but was the same price and had 5% lower performance than the 270. The EVGA GTX 760 at the time was a good $70 more expensive (40%) but it only had about a 10-15% increase in performance. Since I was going for a budget build I was very happy with my choice for the R9 270. It was the sweet spot between price and performance.
The fan runs very quiet and gets to 1,300 RPM when gaming. My only gripe is the card does not come with an ATI or MSI metal sticker that I could put on my case. Also, the HDMI sound did not work with drivers from MSI, the official ATI beta drivers worked well and solved the problem, though.
Case (Silverstone SG05)
Researched a bit and debated between Silverstone SG05 and the Corsair 250D. Since the SG05 was $60 cheaper and also quite a bit smaller, I went with the SG05. The case was actually a bit bigger than I imagined, although it is probably close to the physically smallest you can get if you wanted to go with a full sized GPU. The case had a lot of areas to hide cables and it made cable management actually quite enjoyable. The build quality was acceptable (and I could see how the front cover could easily get damaged as others have pointed out). The stock fan was fairly quite at a max of about 1200 RPM. I might get a 2000 RPM fan to pull more air in.
Probably the biggest limitation was the 86mm requirement for CPU coolers. This won't affect me now as I'm happy with the Intel stock cooler, but really limits my options with coolers later, and makes getting liquid coolers impossible unless you modify the case, which I didn't want to do.
Power Supply (Silverstone SFX 450W Bronze)
I just got the Silverstone SFF power supply because I didn't want to spend time researching all the sizes. I got the bronze version and it wasn't modular. This made the power supply cables were a bit challenging, especially when inserting the 3.5'' HDD, but it wasn't too bad. It was quite silent (stock CPU fan was loudest) and did not heat up too much during gaming.
The SG05 case had USB 3.0 headers but the Asrock H81 mobo did not. I had to order a $5 converter. Works great now.
Added Razer Abyssus gaming mouse and Steel QcK Mini mouse pad.