KOF 2001 is one of my favorites, along with KOF 96 and 98, and ranks as my top choice amongst the 00 KOF titles.
I love the music in this game, but also the primary genre of music I listen to is Drum and Bass, and many of the tracks in 2001 are breakbeat/dnb. KOF 2001's soundtrack was pretty different from any other KOF game. Nearly every other KOF game has rock inspired soundtracks, and 2001 goes in a different direction.
The track "Ruler of the Dark" sounds great.
Its fitting because some darker characters arose during this period, such as Lin and K9999. Lin looks like some sort of evil mummy in a way with his skin color sets, and stance. Lets not forget K9999 made his premiere in 2001. A clear ripoff from AKIRA, but.. still awesome to play as this character. 2001 is the one game where both of these chars are playable together (unless you count 2002 UM).
2001 did mark a trend in washed out backgrounds that persisted through KOF 2002 and even some of 2003 and SVC. However I still think it has some memorable stages like the one where those dudes are swinging their hair around, and the Mexico stage. The race track stage is terrible though.
KOF 2001 may not be everyone's cup of tea, but it I feel it is unique enough in various areas to warrent some recognition.