Of course, if we want to beat the system in Monopoly and still stay legit, we could start by working out the probabilities of landing on the various squares. The easiest method of doing this is to run many computer trials; the result of 10 million moves shows roughly the following chances of landing on each property:

Pink & Light Blue: + 0% chance
Green & Yellow: + 5% chance
Orange & Red: + 22% chance
Brown & Deep Blue: + 2% chance (adjusted for only 2 properties)

The reason Orange is so popular is because of the "Go to Jail" square; this effectively means a player has twice the normal chance to be on the "Jail/just visiting" square... throwing a 6/8/9 from here lands you on an Orange

Or, we could find the amount of money you need to spend on each set of properties before the rent is 750:

Brown: n/a
Light Blue: n/a
Orange: 1760
Pink: 1940
Deep Blue: 1950
Yellow: 2150
Red: 2330
Green: 2720

(adopted from the book "Taking Chances" by John Haigh)

Note: I'm assuming the following colours when progressing around the board from "GO"; these are used in most European versions anyway: Brown, Light Blue, Pink, Orange, Red, Yellow, Green, Dark Blue.