Lacquer or Oil are the most popular finishes for floors.
Lacquer usually comes in a form of polyurethane and creates a seal across the grain of the wood, preventing dirt from getting into the grain of the floor.It generally requires less upkeep.
Oil sinks into the grain of the wood and gives a more natural appearance, but requires more regular cleaning to ensure no dirt settles into the grain of the floor.
Although i would guess lacquer is the more protective finish, oil is easier to repair isolated areas if neccesary, without sanding the whole floor. where this is not really possible with lacquer.