Need a recommendation: Skylake i3/i5/i7?

Hello world,

First post here. I learned about unRAID when trying to figure out what to do with my dying Win7 HTPC and deprecated Amahi 6 on Ubuntu 12.04 machines.  I found unRAID (through glowing reviews on Reddit and while Googling features that I wanted on my new build).

I'm preparing a new build.  This will be my first unRAID build, and I'm looking to centralize the functions of my two existing machines.

The big question: i3/i5/i7? (and whether 16GB RAM will be plenty, or if I should bump up to 32GB).

I went into way too much depth about my build on Reddit (including PCPartPicker details) at https://www.reddit.com/r/homelab/comments/4f3zxv/the_one_unraid_box_to_rule_them_all_or_i_need/.

Here's the summary of the functions I'd like to be running on the unRAID box (in addition to file serving):

• Plex Media Server
  
• Usenet (SAB/Sick/Couch)
  
• Crashplan
  
• OpenVPN server
  

As I never transcode more than one stream at a time, I know an i3 would be more than enough for the attached, BUT

There are two additional functions I'd like to have the build do:

[*]Surveillance Camera NVR.  I've been running Blue Iris under Windows 7 on an old quad-core Phenom II x4.  Under normal circumstances, Win 7 and BI runs at about 30-40% of the CPU with my current setup.  The x4 has a Passmark of 3533.  This Win 7 install is also running Windows Media Center, ServerWMC, Plex Media Server, Usenet services, etc.  So perhaps 25% CPU load is attributable to Blue Iris.  Even being generous, and reserving 50% of my current machine's resources for Blue Iris, that would be equal to a passmark of 1750 (not sure if you're allowed to just simply divide passmark scores).  Would reserving one logical core on the i3-6100 (all four cores have a passmark of 5510) and 8GB RAM suffice?

[*]DVR with commercial stripping.  I've been using Windows Media Center and MCE Buddy to date.  I know that TVHeadEnd runs as a plugin.  And I know that I can run Mythbuntu as a VM.  What sort of resources would I need to devote to this?  One logical core and 1GB RAM?  I don't need the commercial stripping to happen quickly (I rarely get around to watching anything within 24 hours of airdate anyway).  If it's relevant, I plan to buy a HDHomeRun to replace my AverMedia A188 (which has no Linux drivers and has been buggy under Windows).  Based on the guide at https://lime-technology.com/forum/index.php?topic=44203.0 it looks like I should be able to run this with one logical core without issue.

I'm not going to be doing any virtualized gaming (I have a separate i7 with a GPU to do all my gaming and photo editing, and I have no plans to alter that system...at least not yet).

So...can I get away with the i3?  Seems like I'd still have just enough juice to transcode 2 720P streams simultaneously.  I really like the i3 because this is going to be a living room build, and I'm focusing on QUIET, COOL and power efficient.

Thank you!