I also remember that thread. I have a flip flop on my street bike with nothing on the flop side.

On the other hand, I have a SS mtb that I really wish had a flip flop. I have to ride to the trailhead and would love to have a higher gear.

So it really comes down to a) is there an appreciable price difference between a single-sided and flip-flop version of the hub? Probably not. and b) do you anticipate extended periods where you would need different gears. For example, if you live in a generally hilly area, you'd probably never flip your wheel because you'd have to climb the hill, then flip it back, descend, and repeat at the next hill. Not really practical. But if you lived at the near a mountain or something, you might ride one gear normally but then have a lower gear on the other side that you would switch to when you want to go up into the mountains.