3970 and 5078/5016. Why? Perpetual chronograph calendar is best executed by PP IMHO even though several examples from other watch houses come close. Why 3970 and not 5970? Size was commensurate to its times and it was a time when PP was worn by the discerning collectors and relatively FREE from the speculative nature of some of the buyers of the 5970 today.
Why 5078/5016? Purity of 5078 coupled with enamel dial execution by PP is amongst the best in this high arena inhabited only by a select few. 5016? The REFERENCE for technological tour de force in a classic size that can and will stand the test of time, future wrist sizes be damned.
Tough to choose just one holy grail