One thing I was going to mention apropos of leather or metal straps. Whatever you go for if you have a decent watch you never know when a link pin will come adrift and probably lost. So, I have found it essential to carry around a small set of watch tools, namely a strap-jig and a selection of those retractable pins. Trouble is with a metal strap is there's a pin to each link, whereas a two piece strap only has two pins.
I think possible you should use a leather strap for one occasion and a metal strapped watch for yet another. I mean, you wouldn't want to go to a mate's funeral looking like a used car dealer sporting all metal- no, a nice conservative expensive leather strap would measure up. Deep sea diving and a leather strap might look out of place there.
There's less chance of losing a decent waterproof watch as you're less likely to take it off in the shower or the bath- or even going in for a dip. But on the other hand I prefer leather straps. Trident do some nice leather straps- are they safe in water do you think? That's a big consideration if you suddenly decide to take a shower with a lady....one might not trust her that much.