This Josh Smith Dunk goes into the vault ahead of the Steve Nash poster. When you consider that Ibaka tried to block it and the point in time of the game and the basket's (and subsequent free throw), it carries even more weight.
UPDATE: Per Steve Holman, who has seen some dunks in his time, from Twitter tonight:
I have done this a long time, but that dunk by Josh is right up there with the vintage Nique in game slams.
It's probably time for a Smoove retrospective of his highly aggressive dunks, but for now, go ahead, revel in this and the team's big win over the Thunder. Nothing else matters tonight. ENJOY!