Gary G
3734
A spendid topic!
I think that I am already on the record as an advocate for "authenticity" and integrity/coherence as critical determinants of value (and appeal to yours truly).
That said, the question of what will be seen as valuable in 30 years' time is a bit trickier! I won't try to decompose the issue into an intellectual argument (for once) but will assert my view that the following will be seen as valuable:
1. Anything by Dufour -- both for its inherent quality and for his role in creating independent horology
2. Most Voutilainen pieces -- particularly the Observatoire and the decimal repeaters, although who knows what else he will come up with
3. The Vianney Halter Antiqua, as a seminal watch that created contemporary horology
4. The "best" of the Greubel Forsey pieces, for their purity and lights-out quality of construction
5. "Characteristic" pieces from major makers (e.g., the original Lange Dato, the JLC Gyrotourbillon, PP 5013) that both stand on their own and represent the very best of their creators. I should probably also mention pieces like the VC skeleton repeater and perhaps the FPJ dead seconds tourb (maybe or maybe not the Resonance, which to me is a poor man's Duality, but that's a topic for another thread!).
Now that I've annoyed all of the Resonance owners, perhaps time to sign off for now...
Best,
Gary G