Only going to put up ones I really know.
Sonic 1
Best: Boss Battles
Runner-up: Marble Zone
Worst: Starlight Zone
Runner-down: Green Hill Zone
Sonic 2
Best: Mystic Cave [1P]
Runner-ups: Winged Fortress, Sky Chase
Worst: Hilltop
Runner-downs: Special Stage, Chemical Plant
Sonic 3
Best: Get the blue spheres!
Runner-ups: Launch Base, Icecap
Worst: Carnival Night [too creepy]
Runner-down: Hydrocity Act 2
Sonic and also Knuckles
Best: Flying Battery Zone
Runner-up: Sky Sanctuary
Worst: Mushroom Hill
Runner-down: Sandopolis Act 2 [also too creepy]
Sonic CD [American]
Best: Wacky Workbench Bad Future
Runner-ups: Metallic Madness Bad Future, Quartz Quadrant Present, Tidal Tempest Bad Future, Collision Course Bad Future/Present/Good Future
Worst: Wacky Workbench Present
Runner-down: Palmtree Panic any/Metallic Madness Present/Good Future
Sonic Adventure [DX]
Best: Open Your Heart
Runner-ups: Casinopolis Main Hall, Sky Deck, Egg Carrier, Ice Cap 1 & 3, Twinkle Park
Worst: Chao races/anything
Runner-downs: Limestone Cave, Red Mountain 1
Sonic Adventure 2
Best: Supporting Me [Biolizard]
Runner-ups: Live and Learn, Mad Space, Sky Rail [math rock/acid jazz = yes], Final Chase, rest of Rouge's levels, Metal Harbor, Pumpkin Hill, Cannon's Core "Cooperation" [K/R]
Worst: Kart Racing
Runner-downs: City Escape, Mission Street, Meteor Herd, Radical Highway [for mostly being just a riff, albeit a good riff]
Sonic Heroes
Best: Hang Castle
Runner-ups: Mystic Mansion, Lost Jungle, Frog Forest, Egg Albatross, Egg Emperor, Egg Fleet, Seaside Hill
Worst: Every theme song ever
Runner-downs: Grand Metropolis, Power Plant, Bingo Highway, Casino Park
Shadow the Hedgehog
Best: Lost Impact
Runner-up: The Doom, Iron Jungle, Gun Fortress, Prison Island
Worst: Glyphic Canyon
Runner-downs: Almost Dead [lolquasimetallica], not crazy 'bout the rest of the themes either
I also hear Unleashed's music is pretty consistently great. Spagonia [Night] is probably my favourite that I've heard so far.
Edit: listened to Shadow's soundtrack again and came to the conclusion it's pretty great.