It depends on how desperate you are to play the game!
If you get it at launch you pay a premium at $50. If you wait for a sale (it was a daily deal on the current steam sale a few days ago) then it might come down to $30. Wait a year more and next sale its down to $10. So it depends on whether you can wait or not.
I generally play games that are a few years old. Then by the time I'm done with those, the current games are a few years old
I might make an exception for L.A.Noire though. Generally boxed adventures are not available in stores where I live, but since L.A.Noire is published by Rockstar, its on the shelves. The box version is available in stores here for $18
