Soundwave on 23 September 2014
Pretty safe prediction, they are about 30-40% behind the GameCube and they have already spent 2D Mario, 3D Mario, DKC, and Mario Kart. That's 4 of their 6 biggest selling home console IP (minus the Wii/party games that have had their sales fall off a cliff).
The gap is not going to close anytime soon either as the GameCube's biggest holiday was 2003, meaning that GCN lead will grow larger after this holiday is done even with Smash Brothers (GameCube got a $99 price cut + Mario Kart: Double Dash).
