At work, I use almost all Windows based applications, none of which are open source At home I use FreeBSD for a lot of things, and that's all open source. I also use a lot of software I've written myself, some of which is open source, but mostly not.

Have them:
Dismantle a desktop PC.
Take apart a video monitor (CRT or LCD).
Tear down a hard drive.

Congratulations -- they're qualified to be a computer recycler.

How many people have actually used and can make a valid comparison of all these distributions?

(cough, cough)
640K

Touchscreens are OK for applications that you need to use for 5 seconds, like a kiosk where you would look up some information and then go on your way. But for continuous use, they are not the right interface.

My high school (ca 1972-1975) had a computer lab with 3 or 4 desktop programmable calculators. I think they were CalComp or Monroe. They had a system where you could write a program on one to three punch cards that the calculator would read in and execute. The punch cards were standard IBM size, but they had pre-perforated holes that you would push out with a stylus on a special card holder. You could fix a mis-punched hole by gluing the chad back in place.
I spent a lot of time learning all about those machines and exploring their limits. I wrote many programs that used the maximum number of instructions possible, and learned a lot about program optimization that way. I discovered some undocumented op codes that allowed some interesting printer operations and wrote a program to print sideways banners on the tape printer.

I have been using the same keyboard layout since 1989, when I first got a Northgate keyboard, and I refuse to switch. The function keys are in two vertical columns to the left of the main keyboard and on the left-hand side of the main keyboard I have, from bottom to top, "Alt", "Shift", "Ctrl" "Tab" and "Esc". (Caps Lock is safely out of reach just to the left of the space bar). There is a full numeric pad on the right as well as a cursor control group just to the left of the numeric pad.
I find this layout much more efficient ergonomically than more modern keyboard layouts, which sacrificed good layout for compactness.

One of my main computers that I use almost every day is a Pentium 3 Win98 machine, with four different parallel port devices (attached through a switch to the single parallel port on the computer) -- an HP LaserJet Series II printer (still making clean prints), an EPROM programmer, a security dongle and a JTAG adapter. I also have (and use regularly) a Houston Instruments plotter connected to this computer via RS-232.

Another advantage of using a drive filled with helium is better thermal conductivity than air (0.142 vs 0.024) . The heat generated by the inner workings of the drive will be conducted to the outer case, keeping the inside cooler.

The answer to this question is, "convenience."
Imagine the scenario where you recharge your commuter car overnight. With a plug system, you will have to remember to 1) plug in the system when you get home and 2) unplug it again when you leave for work the next day. If you forget either of these steps, you end up with either an uncharged car in the morning, or the plug gets ripped out of the side of the car when you drive off.
If you can drive over an inductive loop when you park, your car will charge automatically when you park and there is nothing to disconnect when you leave again.

As I recall, Robert Heinlein's 1952 story, "The Rolling Stones," predicted 3-D printing, or its equivalent, when referring to a method of making repair parts for a rocket engine.

With all the old hard drives that wear out or become obsolete, I wonder if there is any effort being put into recycling the rare earth magnets they contain, or if old drives are just dumped by the ton into landfills.

Same here. I didn't write much code, but I did a lot of editing and got several things to start working. Lines of code written is a terrible way to measure productivity.

Maybe one hour a week on average:1/168 = 0.595%

My HP Laser II cost me $20 when I bought it at surplus several years ago. After fixing a broken sensor and receiving several new toner cartridges through Freecycle, I have a reliable, good quality printer that has printed reams of material for me, not to mention whatever its previous owners printed. Yes, it's slow, but I'm usually not in a big hurry.

I have a 10C sitting on my desk beside me right now. I also have a well-used HP-21 at home. I learned to use RPN back in 1975 and it quickly became second nature to me. Since then, I can't stand having to use a calculator with an "=" button.
I hope my 10C and 21 last for many more years, because I can't buy replacements any more. A few years ago I bought an HP-41, which was nice while it lasted, but as a newer model, it was made with inferior components and stopped working one day.
I really wish HP would reintroduce the HP-1x line, built like in the old days -- to be the BEST calculator you could buy, not the CHEAPEST.