Update: I replaced the original old and slow hard drive with an SSD. I know the SSDNow v300 has a bad reputation, and the one I got is one with the slower flash, but I got it dirt cheap after a rebate and it is still much faster than an hdd so I am happy with it.
I wanted to build an HTPC to stream my movies, music, tv, etc from my main gaming computer and also to play some of my more casual video games from the couch. Also when SteamOS is released, I may consider installing it on this computer and streaming some games from my main rig to this one if that will be possible. All of my computers get the dubious honor of being named after bulgarian pop singers, and so this one is Boris, after Boris Dali (http://www.youtube.com/watch?v=6QTJ-BOxf1A).
This was my first build with an AMD chip, and the A6-6400k was a pleasant surprise. My motherboard automatically overclocked it to 4.2 Ghz. It has handled 1080p video and blu-ray playback without any problems, and it doesn't feel slow. I don't plan to throw any heavy games at it, so I'm not too worried about graphics performance, and I think it was a good choice. I may upgrade the cooler at some point, but it will mostly be for looks and to keep things a little cooler, since the stock cooler isn't bothering me at all for now.
I don't own/watch a lot of blu-ray, but I wanted one around, just in case a friend brought one, or I decided to rent something. I found an external blu-ray drive on amazon for about $35, pulled it from its casing, and it worked perfectly in my case.
I think that memory was more expensive when I was looking than it was the last time I was looking, possibly because of the Hynix fab plant explosion? Anyway I wanted to keep the build price relatively low, so I found 4GB of 1600Mhz DDR3 on ebay and got it for $40, and I think it is enough for this computer anyway. My case is the Fractal Design Node 605, which I generally found to be very nice to work with. I didn't like the fan layout, so I added an extra 120mm bitfenix fan that was sitting around unused since it came with another case. Now the fan on the left and the right are set as input, and the fan in the back next to the cpu is output, and I think that is giving me much better airflow. The fans make some noise when turned all the way up, but I use the middle setting on the built in fan controller, and any noise is not noticeable with the background noise in my apartment, and cooling is adequate for my APU.
The hard drive is probably the worst piece of this build and will almost definitely be upgraded. It was the original drive in a 2008 macbook which has long since been sold. It still works though, and decided to use it as a stand in until I see a sale on an ssd that looks good. I won't necessarily need a lot more storage, since almost everything on this computer gets streamed from my main rig, but it would be nice to get the speed boost from an ssd. The 6" sata cables that I used were surprisingly hard to find, but I would recommend them to anyone looking at the Node 605 case. If I had a drive in the first possible slot next to the front of the case I might have needed an 8" cable, but for the others these were perfect.
I'm still working on an upgrade or two, controllers, remotes, etc but overall I am happy with my attempt at putting together an htpc with an AMD apu.