If I were to keep just one of yours, it might just be the Cyclops. And I would likely choose to equip it with 8sp 7400-series or 9sp 7700-series Dura Ace, though I'm sure the modern group on there is very nice to work with.

I have a soft spot for Canadian bikes, 80s/90s roadies of good quality, and Cyclops in particular.

If I were to keep just one of mine, I might be forced to opt for one of my modern bikes, perhaps my Black Mountain Cycles Monster Cross or my Lynskey Cooper, as I don't think I could operate in daily life or do what I want to do with my time away from work without a machine that is highly capable on rough gravel, loaded down with luggage, etc. - as much as I love an unencumbered classic road bike! Sacrilege, perhaps - but definitely a hypothetical, as I don't see my own Cyclops (or Mercian, or Marinoni...) leaving the stable anytime soon.