Goat City
Dumpster's Lament(In a true showing of fandom I have 3 versions of this. The one in the game, the 2:48 one, and the 5:10 one... I also have frog 'n care, and prolly all the other music that was on the media page of the old TNM site.)
WC ending
Llama combat
ABI ambient (Is it just me or does anyone else notice a similarity with this song?)

Hey do you have Inherent In The System by Tre? I lost that ages ago, and I'd really love to get it back.

Two favorites:

- Combat song from Goat City (best! Don't know why )
- PartyZone ambient

... plus other great tracks that I don't remember right now.

The Intro Music. I played it so loud my entire neighbourhood wanted to know where it was from!!!

My favourite ones are Goat city and ABI ambient.

That's how my playlist looks like:

WCHQ_Combat.ogg
WCHQ_Conversation.ogg
Despot_Combat.ogg
DXI_Ruins_Ambient.ogg
FCCorp_Ambient1.ogg
FCCorp_Ambient2.ogg
FCCorp_Combat.ogg
FCDowntown_Ambient.ogg
FCDowntown_Combat.ogg
FCSlums_Ambient.ogg
FCSlums_Ambient2.ogg
FCSlums_Combat.ogg
GoatCity_Ambient1.ogg
GoatCity_Ambient2.ogg
GoatCity_Combat.ogg
PDXHQ_Ambient1.ogg
PDXHQ_Ambient2.ogg
PDXHQ_Convo.ogg
PDXHQ_Combat.ogg
Stereo_TheSynapse.ogg
ABI_Underground_Combat.ogg
SolsBar_Ambient1.ogg
SolsBar_Ambient2.ogg
SolsBar_Combat.ogg
SpaceStation_Convo.ogg
SpaceStation_Combat.ogg
Unrealistic_Ambient.ogg
Partyzone_Ambient.ogg
TNMCredits.ogg
ABI_Official_Convo.ogg
DXI_MCR_Conversation.ogg
DXI_MCR_Combat.ogg
Stereo_DXPS2Theme.ogg

It's a single-loop playlist so the same song plays in a loop changing it when I want to. Most of the time though while game-deving I play one of these in a loop as these work very well as bg-music even when running 2+ hours in a loop:
FCSlums_Ambient2.ogg
PDXHQ_Convo.ogg
FCCorp_Ambient2.ogg
WCHQ_Conversation.ogg
DXI_Ruins_Ambient.ogg
SolsBar_Ambient1.ogg
Unrealistic_Ambient.ogg

Funny everthing that spoils the storyline has to be Censored (THERE R ALIENS IN THE HTTP Gamespy) Well like that. even in the Spoilers Are Permitted Zones. (lol)
Alright, Back to topic.
Slums ( Day One Version ) gets me excited.
all ABI tracks (one of the combat tracks has a little reference to a ZODIAC track)
Space Station (Who wouldnt?)
TNM Main Menu Music ( Sounds like an 80's TV Series intro to me , pretty nice job LeoBad)
Downtown Combat (Cool but not enough action in Downtown)
Endgame music

Goat city combat, llama temple combat\death, radish adventure ambient, space station combat\convo, ABI underground ambient\combat\death, pdx combat\death and WC combat

Lets see:

Goat City (I have 3 versions of this, the original, a second one and the final version, like the original as it seems quite peaceful with piano, but also like the final one used in the game but I prefer the second version if anyone knows it, has a good drum beat.)
Dumpster's Lament
Ghandiah's theme (I think this is the original TNM theme, had it from when it was posted on TNM website years ago, in the early days of TNM. I kind of prefer it over final one.)
Sol's Bar Part II
Despot Combat Music

If I remember any more, I'll post them.