If the $800 were only for a watch, and a new one I would be considering the following in this order:
1) Christopher Ward Diver
2) Zelos Diver GMT (pretty much all they make)
3) Hamilton Murph Watch
4) Ocean Crawler Bolt
5) Squale Diver
6) Seiko Alpinest GMT
Used opens up a whole new world of watches to consider.
For the most Value, spend $800 on a Zelos, put it away for two months, then sell it on Ebay for $1,000 or more, buy another watch.
If it were $800 their are plenty of firearms or optics I would like to get and that would be an entirely different conversation.
I knew you would have some great suggestions ! - A Squale did cross my mind too, but i didnt even think about a Christopher Ward - a Trident Pro would definitely be in this price category