2012 is on its way out, but the great music it left behind is going to be ringing in our ears for years to come. Two talented rappers—one a rookie, the other a vet—released albums that some are calling classics. Introspective, thoughtful R&B made a serious comeback. Some of rap's biggest crews came together for epic posse cuts that rap hasn't seen the likes of since the '90s. Here, BET.com runs down the 50 best songs of 2012, the ones that defined another great year for music.