Sonic Adventure 2
Released 5 months after Dreamcast announced its bowing out of the hardware aspect of video gaming, this game had it all: Fast gameplay, lovely, vibrant graphics, VERY good music/OST--though the story was pretty much the same...Dr. Robotnik uses *such and such*/creates *such and such* to take over the earth. But it was a formula that seemed to never fail in Sonic Team's 10+ years of the blue, spiky-haired furball.
Though, after SA2/Battle (GCN), things went to the trash with Sonic Heroes, Shadow the Hedgehog, and the newly released Sonic the Hedgehog for nextgen. The all around shoddy gameplay and botched controls SOMEHOW made its way to the nextgen Sonic, making it the worst outing from Sonic Team...EVER.
Jam it back in, in the dark.