Maybe a planet with unusual resources, like say rich dilithium deposits, but I don’t see a planet being uniquely ideal for leisure. You can create any kind of resort or facility you want on any planet that has the right climate zone somewhere. Especially with transporters, because you don’t also have to build a spaceport there.

edit: one thing I just thought and mentioned in another comment is unique genuine experiences, such as surfing at a particularly spectacular beach.