This is basically a list of music I think that would make for some excellent remixes (Besides being good tunes in the first place). Many of them do not have any remixes on this site and for the ones that do, I think more are in order (;^D) . One more thing is that my taste is along the lines of [ techno / industrial / trance / classical ] and I was thinking of something along those lines when making this list. In essence, I'm saying that a jazz remix of most of these tracks wouldn't work very well...
Super Mario RPG
Battle with Culex
1st Battle with Smithy (where he looks like a diabolical Santa o_0)
Major Boss Battle (i.e. Axem Rangers, Exor, etc.)
Mini-Boss battle (i.e. Hammer Bros., Croco, etc.)
[*]Chrono Trigger
Battle with Lavos' 2nd form (Inside the shell)
Final Battle with Lavos
[*]Super Mario World
Vanilla Dome Map Screen (Possibly good for a hip-hop type remix)
Bowser's Valley
Special Zone
Star Road
Ending credits
[*]Donkey Kong Country
Gangplank Galleon
Cranky's Theme
Funky's Fugue
Fear Factory
Forest Frenzy
Treetop Rock
[*]Donkey Kong Country 2
Battle with K.Rool
Lost World Map Screen
Ice Cave Level (i.e. Black Ice Battle)
Jungle Level (i.e. Animal Antics)
Ship Hold Level
[*]Donkey Kong Country 3
Mountain Level (i.e. Kong-Fused Cliffs)
Pipe Level
Tree Level (i.e. Ripsaw Rampage)
Factory Level
[*]Plok
Boss battle (i.e. Bobbins Bros., Womack Spider, etc.)
Beach
Creepy Crag
Cavern (The level after Creepy Crag I believe...)
Fleapit
Plok's House
[*]GoldenEye 007
Antenna Cradle
Train
Silo
Aztec Temple
Egyptian Temple
Streets
Surface 1
Bunker 2
Depot
Nearly all of the "X" versions of the musics are good...
Pause screen a.k.a "007 Watch Theme"
[*]Perfect Dark
Alien Conflict
Main Menu
dataDyne Central: Extraction
Area 51: Escape
Deep Sea: Nullify Threat (there is an official remix of this I've only heard in USF format which is decent...)
Nearly all of the "X" versions of the musics are good...
[*]Turok 2 : Seeds of Evil
The Death Marshes
Lair of the Blind Ones
Hive of the Mantids
[*]Star Fox 64
Final Battle with Andross (i.e. The brain, not the face)
Sector X
Macbeth / Titania
Area 6
Bolse
Warp Zone
StarWolf's Theme
[*]Legend of Zelda: Ocarina of Time
Forest Temple
Mid-Boss battle
Dinosaur Boss Battle (The boss in Dodongo's Cavern has different music than the other bosses)
Chamber of Sages / Temple of Time / Legend of Hyrule (They're basically the same...)
Inside Gannon's Castle (This is where Gannon is playing the piano, this is also in Zelda 3 done without piano)
1st Battle with Gannon
2nd Battle with Gannon
Shadow Temple
Zora's Domain
Potion Shop
[*]Paper Mario
Huffin' And Puffin' (Battle with Huff N Puff)
King of the Koopas (Final Battle)
[*]Doom
E1M8
[*]Doom 2
Map 32
[*]Doom 64
Into The Void (I think this was used on other maps as well)