For me its "Stranger in Moscow." The beat at the beginning. The way the melody fades in. The entire mood of the song. MJ was going through some shyt when he wrote that song, and I love the way he really used his music to inspire, address world issues, and personal issues. I had the song on rotation for like an entire week the first time I heard it after I downloaded his discography. My favorite album from MJ would definitely be HIStory because every song is phenomenal. RIP MJ.