I voted 40-50 mil.

To give an update about the standings of the poll.

 lower than 10M 35 5.09%  
10M-20M 116 16.89%
20M-30M 120 17.47%
30M-40M 120 17.47%
40M-50M 93 13.54%
50M-60M 83 12.08%
60M-70M 45 6.55%
70M-80M 30 4.37%
80M-100M 15 2.18%
 bigger than 100M 30 4.37%  
Total: 687

Assuming this is a successor to both 3DS and Wii U, and that Nintendo react aggressively if Switch enouncters difficulties (as they did with 3DS, but didn't with Wii U), I would say 8 million from launch to the end of this calendar year, and 50-60 million in 6 years.

if its just a home system then 10-20million
IF they also treat it as a 3DS replacement and start making Pokemon for it i would say over 40million

its hard to guess with them now doing iPhone games and things tbh..

I'm convinced that March is like a soft launch for the die hard Ninty fans, they know will buy whatever they put out. For the rest of us there is the fall window. 

@bolded sounds like the damn gamepad

I'll go with 45 million lifetime and 8 million first year (actual first year not the end of 2017)

About 50-60 million lifetime, because the price will hopefully drop heavily eventually and many 3DS owners will jump in.

The wii u threads averaged about 40 million and we ended up with about a third of that. But that was on the back of the success of wii so expectations were probably raised.

If it is a unified platform and we get multiple sku's all running the same cartridges do they all count under one total or are we actually voting for the first Switch release only. I don't think this sku will do that well but I think later revisions and devices running the same software will do much better.

In 2021 there could be a budget Switch portable like 2DS getting huge sales and the must have device for Christmas that year for young children, does that count in these figures?

Well, we usually count all SKUs together that mostly run the same games. DSi had DSiWare and a few games that used the camera, 3DSXL had Xenoblade, but in both cases we counted it as the same console. Same will happen with PS4Pro and Scorpio.

I'm going to say 30 million if and only if it's gets similar games to 3DS ie pokemon etc