The Oyster Perpetual line is the prototypical Rolex model family in that the Oyster case is now part of every Rolex model except the dressy Cellini. If you want the most basic, highly water-resistant Rolex on offer, you should absolutely consider a 34mm OP.
The Rolex Explorer is an absolute icon, its predecessor having scaled Mt. Everest in 1953. The current steel model in 36mm is a fabulous watch made for rough adventure, but its simple, no-frills looks makes it an appropriate everyday wear — and even a candidate for dressier occasions in a pinch.
Truly, where else are you going to find a well-sized dress watch in precious metals, appropriate for both male and female wrists, available in such a wide variety of dials, case materials, straps, and more?
The vintage Air-King ref. 5500 is but one of many beautiful 34mm watches Rolex made between the 1950s and today, and you can get one in one of various colors, on a steel bracelet, for like four Gs.
Back in the 1950s, ‘60s, and ‘70s, Rolex made a series of non-chronometer-signed, entry-level, manually wound steel Oyster watches with date windows. Measuring 34mm in diameter, they’re small by today’s standards, but still make fantastic entries into the Rolex market at large, and the vintage Rolex market more specifically.