I own most of the official Konami x Mondo releases of Castlevania on Vinyl (and yes I know how rediculous that is from an audiophile's standpoint), so I guess Castlevania is my favorite.
I really just came here to agree with you that Xenogears has an amazing soundtrack though.
Ragnarok Online, hands down
Aside from MMOs, i really like these :
- TLoZ : Majora's Mask
- Resonance of Fate / End of Eternity
- Boktai (serie in general)
- Resident Evil 3
- Tales of Graces f
There's a few other game OSTs i like, but these stands out imo
Doom Doom 2 Doom (2016) Quake MGSV Every guitar hero and rock band game
Anything Pokémon, Super Mario (especially Galaxy 1/2), and many things Sonic. Special mention to Pocket Card Jockey, just because no one knows about it but it's still an excellent game with an excellent score. Written by the same composer as many of the Pokémon games (Go Ichinose). Edit: Seconding Pokémon Mystery Dungeon.
Pokemon Mystery Dungeon deserves a mention in this thread! YuGiOh Dungeon Dice Monsters has a few really nice tracks as well Shatter's OST is so good, I'm not sure if I spent more time playing the game (I played it a lot in the past) or listening to the OST Scott Pilgrim Vs. The World Video Game Soundtrack by Anamanaguchi is basically cheating but whatever :'3
EDIT: Checking my music folder Black Mesa (the fan remake) has a few really nice tracks as well
Oath of Felghana Metal Gear Rising Revengeance Ar Tonelico 2 Lords of Thunder (TurbographxCD) Etrian Odyssey III Super Arrange - Unrest: Their Own Brand of Justice Ys Origin Super Arrange Version - Over Drive BlazBlue: Chrono Phantasma OST Wir fliegen - Xenoblade Chronicles X Valkyrie Profile 2 OST [Alicia Side] - Never Surrender God Hand - Devil May Sly Monster Hunter World - Battle / Rotten Vale Doom (2016) has already been mentioned, Ocarina of Time,Chrono Trigger, Final Fantasy 6, Undertale (not linking these)
Think I went a little too wild there, I have a lot more but I will stop here...
A bit scary but the better music i ever heard in a video game, from Resident Evil 7 - Go Tell Aunt Rhody A bit strange btw,idk why i like it