Guess I'm first.
Well, I'll be honest. I don't have
a stethoscope - I have three. Yep, I know, it's bad (And I'm not even a nurse yet.)
Prestige Medical Clear Sound
Littmann Classic SE II
MDF 777 (my favorite)
I've worn my stethoscope all the ways shown in the link in the OP, except for the bottom two; I always have a stethoscope when I'm on the floor, and I would never use the last option. (Though a local doctor I know does have a tendency to wear his like that...hmmm.

) Looping my stethoscope (like "The Lasso") is a lifesaver. I stopped stuffing my stethoscope in my pocket to protect it from falling (I did a lot of bending during NA clinicals) once I learned that trick. Works like a charm!