here let me give you a list of times it would be ok.

vs the giants go ahead and punt it Eli is a little ***** and wont drive the field
Vs the colts go for it, get 2 yards and win the game, otherwise peyton has the tools to get the win
Vs the saints go for it, Drew brees is insane go for the win
vs the vikings Punt it, Favre will throw an interception
Vs every other team in the NFL punt it,