1. My now favourite was mentioned, but I'll mention it again - Monte Carlo Freeport. The whole system is awesome, the connection to a race track nearby fits nicely (Sombs I beg you, add the Provence racing ost already) and overall vibe of Monte Carlo is very compelling to me. And to others it seems.
2.Ames Research Station. If Freeport 11 is the last (neutral) installation on the edge of humanity's reach, Ames is similar. But when Omicrons are scary and dangerous because if harsh conditions and aliens - Kepler bears even scarier nature - one wrong step and you are lost in the darkness that no light can pierce and where Ames is the only safe harbor, constantly fighting for its survival.
3. Shasta Orbital Skyhook. Even though Baffin isn't even near to be popular, its solitude only adds up to the vibe. And I only imagine how cool Shasta would look if it was possible to fully integrate what's written in the infocard.