HTPC+NAS 2 Diff PC's or HTPC\NAS in One PC?

[Spookshow]

Title says most of it. I am moving soon and going to change my setup. Instead of using my Main rig as the house server, I am going to be building a new PC for NAS and might as well build a new HTPC. 

So to get down to it my question is should the HTPC also BE a NAS? If so what processor is enough but not to much? If it should be 2 diff PC's again how much processing is enough but not to much.

The features I will be using are as follows:

• NAS
  

1. FreeNAS (storing main movie files and misc backup data/folders)
   
2. Will need to be powerful enough to stream to 4 diff sources at 1080p
   
3. Room for 3 WD Red 3 TB drives and an SSD
   

• HTPC will be running KODI (XBMC) via Ubuntu
  

1. KODI (XBMC) via Ubuntu
   
2. The HTPC will need enough power for decoding 1080p movies
   
3. Steams in home streaming
   
4. Netflix and Hulu streaming.
   

•  If both in one PC then Ubuntu for Steam in home streaming + Kodi 
  

Do you recommend a Xeon? If so which one is enough power?

I will be going with a Gold+ PSU to save on power

Will going with a combo unit save on electric? Will it compensate for the cost of higher cost of the PC?

Are there any features I have not listed that would help with feedback or is there anything else I should look into?

 

I will be wiring the place with 10 gigabit Ethernet

I have an old i5 2320 I can use for either the NAS or the HTPC (or the combo if its strong enough)

I am not to concerned with budget (not saying there isn't one) just as long as I can justify it then it fits. 

ITX is my friend

Any feed back is greatly appreciated. I am new to the Server world and not sure how much processing power I will need. 

 

I am mostly looking for CPU recommendation but any pcpartpicker build links for over all recommendations are more then welcome!

[soaringchicken]

To many words foe me, sorry if I missed something I just skimmed over it. I think an 8320 (due to it's 8 cores) would be good, due to the fact that it would handle being a NAS + HTPC better. As for the gold PSU, there isn't really that much of a difference between a bronze and a gold, but it depends whose paying the power bills

[RevoltTrain]

I'd go with a 8350 and a nice PSU, preferably a gold rated PSU as it seems this is a rig that will be live 24/7