I vote a 5512 or 5513, plain and simple classic! Vintage subs are a great investment. I can tell you my gen Tudor 7016 purchased ~5 years ago was about $1500 and now are rarely seen for less than $2500-3000 -that's a conservative range too.
My gens:
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Sometimes a better value is to get an entire Datejust watch, you can find them sometimes $1000-$1400 and use the movement. This way you can always resell an entire watch as well. Just my $.02
Agree, they're great. The Modena is the strap same I have on my 1665 in the pix above. Also no rubber stinkiness of the vintage Tropic straps -I love the look of them but a lot of them you smell before you enter the room....
A rally strap is always a good option... Below is one on my MC, although this strap is 20mm -I've mounted it on a 19mm case. There are probably 19mm out there if you look hard.