So with the fx4138 you don't think it will be enough for my needs?
Any FM2(+)/LGA-1155/LGA-1150 CPU you can buy is "enough" for basic use, including HD streaming. This is coming from someone who has used everything from the very basic Celeron G465 over Pentiums, i3s and above. My media-centre is A10-6800K based, so its not that I'm particularly biased towards Intel.
My problems with the FX4130 are twofold. First its first generation "Bulldozer" based, which means lower per-module performance (at least 10-15%) then the newer "Piledriver" modules used in the APUs and the FXx3xx CPUs. Two, it will use a lot more power for no gain in performance vs a two module APU.
I'd urge you to at least consider a Haswell Celeron/Pentium with a good H81 board, a 120GB SSD (I can recommend the 840 EVO) and 8GB RAM. That combo will do everything you ask of it, and run cool, quiet and be very frugal with power consumption. That way you'll always have the option of upgrading with a used i3/i5/i7 down the road.
Are you calling the A6-6400K a "single module AMD APU"? I can't keep up with what AMD considers a "core" anymore.
The Bulldozer/Piledriver/Steamroller architectures use modules that consists of two "cores", but they share fetch, decoding and FPU. That means a module is not "really" two cores, but more of a singlecore-with-super-HT. Steamroller goes some length towards fixing the module penalty, as it has dual decoders. Bulldozer/Piledriver only has one shared 4-issue wide decoder, so when you load two threads on one module you get a significant penalty in performance. When the APU only has a single module (A6 and below), soon as you run anything you'll run into into that penalty permanently, since the OS scheduler does not have an extra module it can assign extra threads to.
In short with single module APUs, you get all the bad sides of AMDs module design and none of the good.