Station Bay only 'literally pays for itself' if you ignore the opportunity cost of the Bay slot. It will be many years before we get another Enterprise equivalent Bay slot.
We effectively have a choice between building up Earth Orbit (Station Bay), Cis-Lunar (Fusion Shipyard), or other planets (Gravitic Shipyard).
And I'm more interested in good Lunar access and improved Mars access from the Fusion Shipyard. Lunar Cities > Orbital Cities. There are so many more opportunities available by being on the moon.
I am tempted by the Military Bay, as it would be a great force multiplier for OSRCT, and presumably for any future Earth Defence plans, but it overlaps in many ways with the Satellite Bay. To me, the Satellite Bay synergises well with the Fusion Bay, as it will allow us to quickly set up infrastructure around our local neighbourhood. And has Earth Defence applications.
That leaves the Advanced Materials Bay. Which is tempting due to it being a force multiplier for industry, and also other Bays. But doesn't do anything specific.
Then again, there isn't anything else I can really see as being important enough not to do this one. This Bay along with Fusion Shipyard give us our best chance of super fusion reactors as soon as possible.
[X] Fusion Shipyard
[X] Satellite Bay
[X] Advanced Materials Bay