'94. So many great albums dropped that year. After '96 the quality declined but it was slow burn until Soulja Boy dropped and the ringtone era took another chunk of authenticity out the culture. Hip-hop has been too resilient, the fact that it has cooled off now is a testament to that. It had a similar arc to jazz, cooling off in the 70s after a hot period in the 60s if you equate 1960s jazz to 1990s hip-hop.