His other themes, Guitar, Omega, and Rugal in '95, The RR in '98, and Last Dance in 2002, have their fair share of fans too. Although "Last Dance", to be honest, has the smallest circle of fans compared to the other themes. Thank you, Eolith.
And there's the theme of Rugal's son Adel: Revolutionary Etude~R2. It starts out as a Chopin piece, and then goes into full-blown techno. His XI theme, King is even better.
In '98, this got expanded even further, with "Rhythmic Hallucination" being given to Orochi Yashiro alone. In its place, Orochi Shermie gets the subdued yet fitting Fanatic Waltz, and Orochi Chris gets the downright sinister Mad Fantasy.
And eventually culminated into this for KOF 2002: Unlimited Match. Fun.
The New Faces Team's non-Orochi forms also had pretty killer music (no pun intended) in the form of Bloody. Naturally, this too was remolded when Unlimited Match came along. The end result? Re:Bloody.
The Origin of Mind, for Orochi himself. Trippy, ominous, oddly serene, and hard to identify. It fits Orochi completely.
Tears and Sadistic Eyes are among two of the best boss themes in '99, used for the two "hidden" final bosses, Kyo Kusanagi and Iori Yagami.
On the subject of Zero, both the clone and the original were given pretty slick tunes in 2002: Unlimited Match. Original Zero's theme is Testament of N.E.S.T.S., an imperialistic march that has a hint of undying duty and sadness while Clone Zero was given Dark Gravitation, a song that has split some fans on whether or not it's better than "Slasher Zero" (a song that was heralded as "pure evil in audio form".)
The King of Fighters 2000, essentially the old SNK's swan song, has an appropriately awesome soundtrack. Nowhere is this exemplified more than in Kyo's theme, the appropriately titled Goodbye Esaka. You can pretty much feel all the emotions of SNK's (brief) demise.
The rest of the Esaka series is no slouch in terms of amazing muscial direction either. First up was Esaka in The King of Fighters '94. While Funky Esaka is usually passed over due to Soundtrack Dissonance, Esaka? in '96 is one of the most notable (if not the most notable) tracks in the series. In fact, it's so popular that it was reused several times over the course of the series: first in '99 for his clones Kyo-1 and Kyo-2 as Esaka ~Acid Mix~, as a part of the real Kyo's theme in the same game, again for his clone/evil magical doppelganger Kusanagi's theme in 2002 (Esaka '02) and 2003 (Esaka '03), as tworemixes for EX Kyo in XI, and as Esaka!! in 2002: Unlimited Match. Finally, Esaka Forever in '97 memorably brought the Orochi Saga (and Kyo's stint as protagonist) to its fated conclusion.
London March, Billy's theme from KOF '97 (and a majority of Billy's other appearances) also sounds like it'd go hand-in-hand with Guilty Gear. N.D.R., his theme from Real Bout Fatal Fury, is also rocking.
While it might not have the staying power or nostalgic value of "Esaka" or "Tears", Blaze, Kyo's other solo theme from KOF 2003, has its own merits.
Lovehim or hate him, Ash Crimson's themes are deliciously sinister, a testament to just how far he's strayed from the typical protagonistic mold. Splendid Evil in KOF 2003 kicked it off and Joker in XI eventually becomes something akin to Guilty Gear-lite (thanks in part to a killer guitar).
The King of Fighters XII also had a very well-done soundtrack. Unlike previous games, the music used is based on the stage rather than the team or character. There are two versions each as well with one only slightly differing from the other. However, the real eye (or ear) opener is the AST versions of the soundtrack. Here is a preview, and the whole AST can be heard here.
All the music in Garou: Mark of the Wolves qualifies. Take a good long listen to Invincible Mask and tell me it doesn't fit the awesomely heroic pro wrestling phenomenon that is Tizoc, the Griffon Mask.
Finally the twin's theme in Real Bout Special and Real Bout 2.
One word: Kurinkinton (Well, actually, it's four: "Chestnuts and Mashed Potatoes"). Odd name aside, Terry's peppy and upbeat trademark theme is always a great addition to any game. The KOF 2002 version deserves special mention, as do Kuri To Itsu Made Mo ("Chestnuts and Forever") from Real Bout Fatal Fury Special/Real Bout Fatal Fury 2/KOF '97 and Kurikinton ~Gomame Guitar Ver.~ from KOF '98.
Napolitan Blues from '94, Club M ~ Flute Under Blue Sky from '95, and Prolongnation from 2003 weren't too shabby either. Honestly, Terry really can't do any wrong and his teammates (who sometimes drew the short end of the stick when it came to music, especially Joe) benefitted from being grouped with him.
Blue Mary's Blues from Real Bout Fatal Fury Special/Real Bout Fatal Fury 2 and KOF '97. Not only it is a soothing yet melancholy song, but Harumi Ikoma, Blue Mary's seiyuu, actually provides the vocals. (For those who want to hear the non-vocal version, here you go.)
Much like the refreshingly good hip-hop provided by the American Sports Team, a similar case can be made for the themes of everyone's favorite Southtown DJ, Duck King. Whether it's Shitamachi no Abarenbou (The Wild Boy from Downtown) from the original Fatal Fury, Duck Dub Dub from Fatal Fury Special/KOF XI, or Duck Duck Duck! from the Real Bout series, the sound team knows how to churn out snazzy tracks. Props to Kong Kuwata (as in the seiyuu of Duck King and Geese) for actually rapping in a few of Duck's themes.
An ethnomusicologist actually wrote a thesis regarding the music of the franchise. The fourth game, in particular, is said to have a unique blend of Western and Japanese scales for a stylistic result that might have literally never been heard before in video games.
Samurai Shodown Warrior's Rage has a brilliant arranged soundtrack and may be the single greatest music SNK has has ever done. First off, there is Asura's theme which is very dark, yet very tragic sounding. Then we have Haohmaru's appropriately named theme which probably suits him as a character as well as any theme can possibly suit a character. Galford and Nakoruru get probably the best versions of their themes to date, and to say nothing of the boss themes... Gandara has a fittingly ominous track for a giant... THING and Yuga's theme has a dark and terrifying sound that lets you know what kind of being you are up against.