While Resident Evil 1 was a original and sometimes unintended funny game, it was really Resident Evil 2 that started the iconic series I feel. With 2 discs and multiple possible playthroughs with different characters, it was a lot of survival horror for your money. With a gameranking score of 93.13%, it's only outranked by Resident Evil 4 and Resident Evil: Code Veronica.
You can find the soundtrack on Youtube, here.
The soundtrack is wonderfully dark and athmospheric, and the game also uses silence very well.
A defining characteristic of the OST is the eery piano that's present in some of the better tracks. And while the music is not something that mixes well in an OST playlist with other (louder) tracks, it certainly deserves to be added here.
Out of all the Resident Evil games, this is the only game that I could identify by listening to the music, which is a testament to it's quality. If you're a fan of the Resident Evil series, this one is required play.