What is the best set to have in Monopoly?

What is the best set to have in Monopoly?
Monopoly: 9 Best Properties To Buy, Ranked

1 Orange Set (St.
2 Red Set (Kentucky Avenue, Indiana Avenue, Illinois Avenue)
3 Light Blue Set (Oriental Avenue, Vermont Avenue, Connecticut Avenue)
4 Brown Set (Mediterranean Avenue and Baltic Avenue)
5 Dark Blue Set (Park Place and Boardwalk)
6 The Railroad Stations.

Monopoly: 9 Best Properties To Buy, Ranked
  1. 1 Orange Set (St.
  2. 2 Red Set (Kentucky Avenue, Indiana Avenue, Illinois Avenue)
  3. 3 Light Blue Set (Oriental Avenue, Vermont Avenue, Connecticut Avenue)
  4. 4 Brown Set (Mediterranean Avenue and Baltic Avenue)
  5. 5 Dark Blue Set (Park Place and Boardwalk)
  6. 6 The Railroad Stations.