Many love the Firelink Shrine music in Dark Souls. I also love it, but my favourite track might be the surprisingly sombre piano track that plays as you do battle with Gwyn, the game's final (super difficult) boss. Someone has released an amazing Jazz-inspired cover of the track and by God is it ever smooth.
It's actually properly fantastic. If you're one of the elite tribe who saw Dark Souls all the way through to the final credits, you are going to love this. I all but guarantee it.
I've always loved the Gwyn battle soundtrack. Mainly because it's so subversive. After hours of bombastic boss music, the jarring switch is genius. The music is sombre. It reflects the grim, decaying hollow nature of the Dark Souls universe. It also echoes the feelings of most players. You are close to the end. This is the end. The journey is almost over. Such a great track, and such a great cover.