If you are seriously not going to do hardly any gaming at all, just snag that one off of Ebay, it already has a small HD and video card in it that is definitely fine for playing 1080p video. Those barebones novatech systems are fine as well, but I feel like you are overpaying on those, especially with no video card or storage in them. The 750W power supply in those is WAY overkill for what you are going to be doing, that may be raising the price of those barebones systems.
If you think you might change your mind about the gaming, buy the Novatech barebones that has the AMD FX-8 8320 processor, that is by far the best processor out of the 3 systems that you mentioned. Regardless, I think those Novatech ones are a bit overpriced compared to the one you linked on Ebay that already has a hard drive and video card in it. That one is probably the way to go, assuming there isn't drastic price differences in shipping or some other factor that would affect I'm not seeing.
edit - the more I think about it, stay away from those Novatech systems. You'd still have to buy a hard drive + operating system + video card to get them functional. At that point, you might as well just build your own system from scratch, which would either net you better parts for an equal price, or the same parts for a much cheaper price. All those barebones systems are doing is saving you about 30-45 minutes of effort in screwing down the motherboard and snapping in the RAM/CPU.