Subject says it all.
Mines probably Metroid Prime Trilogy. 60 dollar game after taxes, and Nintendo Channel says I spent 96 hours with it. (that's 4 straight days baby)
Not 'technicly' this gen but, I spent 41 hours on Breath of Fire II for VC. 800wp for 41 hours = less than 20 cents per hour.
Worst would be Madworld. Sorry Madworld, I loved you to death but I spent $60 on you and only got 9 1/2 hours of play time. More than 6 bucks an hour for Madworld, ouch.