Thanks for pointing out the n8 update I've been too busy working on my sd2snes cd audio hacks to check. Gimmick music doesn't sound good because of the 5b, it sounds good because it's good music. There's a non-5b enhanced gimmick cart out there and the music still sounds good on that. Are you going to start claiming that snes music sounds better than nes music because the snes has better sound hardware? Hardware doesn't make music good, just good composing.
There's a couple of link to the past songs I always felt are excellent. The dark world theme and the dungeon theme from the light world for those pendant dungeons.
Also mind being a bit more specific about which tracks you like? Saying "the castlevania series" is only listing hundreds of songs.