Is there a best in-game dunk ever? Jordan over Ewing, Vince over Mourning,
Dr J on Coop, Gerald Green or JR Smith with crazy alley-oops? Dominique's follow jam of his own jumper, Drexler had some awesome long distance dunks, Griffin has some remarkable dunks in games (though I don't give full credit to throwing the ball into the basket without touching the rim).
I think the best dunk on this video (titled best dunk from each season) is Jordan's in '85. Look where his foot off when he takes off, and then he still rocks the ball and finishes easily with two hands. Unreal.