I have been running my current nettop htpc for about 18 months now (no build thread created for it) it had served its purpose quite well but I wanted something beefier that could handle anything I threw at it and move the nettop to bedroom duty. We are also cutting the cable cord and see how it goes.
My nettop was a AMD E-350, however I have not been pleased with the drivers so I decided to stay with my preference of Intel and I tried to build it with heat and power savings in mind.
Parts:
Silverstone GD05-USB3.0
Intel Core i3-3220T
ASRock H77 Pro4-M
Corsair Vengenace DDR3 1600 4GB Kit
Corsair CX430 PSU
NZXT Fan Controller
Logitech Mini KB
Not listed that is part of this that I already owned was a 500GB Seagate HD, HDHomerun and DB4 Antenna.
I picked these parts to keep power, noise and heat down. The silverstone case is really great, it has excellent cable management however the fan controller is necessary as my mobo only had two fan leads plus the cpu. You could potentially get away with two fans and upgrade them to something that has pulse width modulation. Thus far in my testing it runs pretty cool while playing 1080p/720p video where the GPU is handling a brunt of the work. I have not tested older rips where the CPU would be used yet.
Some internals… (click for bigger)
I did a lot of reading on silentpcreview.com and came really close to doing a ITX build but JayS pointed out to me that any of my case selections to keep within my budget would have looked like ass in my entertainment stand. I was not about to drop $350 for a HD-Plex case. This solution is what I came up with, if you look at JayS HTPC Build there are a lot of similarities since I made many of his hardware suggestions. Not including the parts I already owned I invested a little over 500 in it.
Some final pics…
Installing Windows 7 on my desk with my 22" Dynex TV
System in its final home with my 60 Sharp LED…