Great music doesn’t age, it ripens. So take this collection of party-ready tunes from the late ’90s through the early 2000s as a hit of nostalgia. But also take it as a musical cross-section of a particular time. From mainstream smashes to underground highlights, hip-hop and R&B to indie folk, one-hit wonders to modern classics, this is the sound of our still-young century. As throwback as it may be, our editors still update tracks regularly, so if you hear something you like, add it to your library.