Thanks guys, maybe I don't need to go Thunderbolt. Maybe Jim will chime in and tell us what he thinks now since he probably has tested numerous builds now. I'm sure he has a go to board or something he recommends now. Thanks again.

interpolated
I had my mind set on i7 although AMD Threadripper with it's 64 PCI-E lanes is an interesting concept.

On paper, Threadripper certainly looks impressive.
Let's hope motherboard support (upon release) is a *whole* lot better than the initial Ryzen release.
Ryzen's initial release was the most rushed/flaky I've seen in the past 30 years.
 
With Skylake Extreme, you have to go with the 7900x ($1000) to get 44 PCIe lanes.
The 7820x ($600) has 28 PCIe lanes.
If you're not running dual video cards... and not running multiple PCIe x4 SSD drives... you'll most likely be fine.
For more complex builds, you'll want the 7900k.
 
 
 

Jtf8751
Thanks guys, maybe I don't need to go Thunderbolt. Maybe Jim will chime in and tell us what he thinks now since he probably has tested numerous builds now. I'm sure he has a go to board or something he recommends now. Thanks again.

It's a multi-faceted consideration... so there's not a "one-size-fits-all" type answer.
 
Thunderbolt provides access to the PCIe bus.  Nothing more... nothing less
For PC users, it's much less "pressing" because we have PCIe slots.
No current generation Mac has any other means to access the PCIe bus.
IMO, That was a bit short sighted on Apples part... along with no means to add internal drives.
 
Microsoft now offers full "PCIe via Thunderbolt" support for Win10.
You have to meet all the following conditions:

• Running one of the latest Z170, Z270, or X99 motherboards that provide Thunderbolt-3 via USB-C port
• Running an up-to-date install of Win10
• Need a USB-C to Thunderbolt adapter
• Your audio interface needs full "PCIe via Thunderbolt" driver

To my knowledge, only MOTU, UA, and RME currently have "PCIe via Thunderbolt" drivers available for Windows.
Make sure you know the details for the audio interface you're considering.
Don't assume just because it's available that it supports "PCIe via Thunderbolt" under Windows.
I've seen numerous folks recommending the Focusrite Clarett series to Windows users.
If you read the fine print on the Focusrite website, the current beta-status driver doesn't (yet) support running a Clarett via Thunderbolt-3 (where Thunderbolt-3 is via a USB-C connection with a USB-C to Thunderbolt-2 adapter).
Thunderbolt support under Windows is relatively new.  Know all the details before buying the audio interface.
 
NOTE (to eliminate some confusion):  
A USB-C port can carry USB-3.1 or Thunderbolt-3.
A motherboard can have USB-C port/s and not have a Thunderbolt-3 controller.
In this case, the USB-C port is carrying USB-3.1 (will not work with Thunderbolt peripherals).
If a motherboard does not have a Thunderbolt-3 controller, it doesn't have Thunderbolt.
If the motherboard has a Thunderbolt-3 controller, you'll need a USB-C to Thunderbolt-2 adapter.
Apple makes one for ~$50.
Some folks have had issues with the Apple adapter... but it's worked perfectly fine in every configuration we've tested (many different PC motherboards Z170/Z270/X99, custom PC laptops, and of course with Macs).
 
The advantage of Thunderbolt-3:
The main advantage of a Thunderbolt audio interface is PCIe level performance.
That means being able to run at ASIO buffer sizes smaller than 64-samples.
Typically, PCIe audio interfaces allow running at a 32-sample ASIO buffer size.  
Some allow going down to 16-samples.
 
While the UA Apollo Thunderbolt series is excellent (both in super low noise and fidelity), the lowest round-trip latency (at a 32-sample ASIO buffer size) is about on-par with the RME Fireface UFX (USB-2 audio interface).
 
The MOTU AVB series (when connected via Thunderbolt) will allow you to achieve sub 2ms total round-trip latency.
 
Running a Thunderbolt audio interface (with a modern build DAW), you won't notice any appreciable performance difference vs. running one of the best USB-2 audio interfaces.
I've compared PCIe and Thunderbolt units vs. the RME Fireface UFX.
PCIe and Thunderbolt won't buy you any additional DSP processing power.
 
Unless you're after sub 3ms total round-trip latency, there's no substantial advantage to a Thunderbolt (or PCIe) audio interface.
 
Note that Microsoft doesn't support "PCIe via Thunderbolt" with any Thunderbolt-2 controller.
If your motherboard has Thunderbolt-2 or offers a Thunderbolt-2 add-in-card, this will not work.
 
Thunderbolt-3 limits your motherboard choice considerably.
With X299 motherboards (just released), the options for Thunderbolt-3 are *extremely* limited.
Even with X99 motherboards, your options are fairly limited.
With Z270 motherboards, there are more choices with Thunderbolt-3.
 
As round-trip latency decreases, the load on the machine increases:
If you plan to run audio projects at a 16-sample ASIO buffer size, the load on the machine is HUGE.
Even the most monstrous of DAWs will struggle with large projects.
16-samples equates to about 0.375ms.
The machine has 0.375ms to process/fill the next audio buffer... or you'll hear a pop/tick.
Double that ASIO buffer size to 32-samples, and the machine has a whopping 0.75ms to process/fill the next audio buffer.
 
 
Knowing all the details, you can make a solid decision as to whether Thunderbolt is significant to your particular situation/needs.