What is the appropriate fuel tank selection to land a 172? On a recent checkout on a C172 I was told to select "fullest tank" as opposed to "both" that I have been doing for years. Given the aircraft is high wing (gravity feed) with no auxiliary fuel pump there should be no chance of sucking air.

Anyone know the correct selection?
You should check your POH but it may just be that the instructor in question was recently flying a lot of Pipers and it was force of [bad] habit.

This POH for the 172S is in agreement with you. 


  BEFORE LANDING 
  
  ....
  
  
  Fuel Selector Valve -- BOTH.
  


You should consult the checklist in the POH that is with the airplane in question to be sure.