I'm really curious what others use, and I'll answer my own poll and post here:
1) android smartphone (currently a Moto X 2014)
2) 2-in-1 (Microsoft Surface Pro 3 -- soon to possibly be a Surface Book, provided my local MS store actually has my pre-ordered one on the 26th ^^;; )
3) tablet (Amazon Kindle Fire)
4) netbook (technically this should be here, but I rarely use it -- I have an older Acer netbook running Ubuntu linux -- used primarily to resuscitate soft-bricked android smartphones ^^;;;)
My Surface Pro 3 is my primary PC. I no longer use a desktop (abandoned last year for the Surface Pro 3). To compensate for the loss of data storage space, I converted an old micro-PC into a network attached storage machine with a pair of mirrored hard drives for redundant data storage.

How many collectors are using touchscreen devices regularly? Is anyone here holding out against smartphones & tablets? Feel free to elaborate in a post, too.

I split up touchscreen laptops and 2-in-1s because they aren't quite the same thing, necessarily. 2-in-1s typically have a "mode" that is all touchscreen driven without use of the keyboard. A regular touchscreen laptop can't be converted to just a tablet. Examples of a 2-in-1 would be a Microsoft Surface Pro/Surface 3 (Surface 2 and Surface RT are tablets, as they run Windows RT and NOT Windows 8 or 10), HP Spectre x360 models, some Dell Inspiron models with the 360 degree hinge, Lenovo's Yoga books, etc.
As you can tell, I'm not as interested in what OS you're using as much as I'm interested in what kind of devices are being used. Most data these days seems to indicate the proliferation of smartphones and inexpensive tablets, but I wonder among collectors what's most popular.