Just about anything by Jordi Savall is worth listening to, both instrumental and vocal. The recording quality is usually very good as well.
Medieval-style music
I'm trying to find good recordings of medieval-style music (not necessarily historically informed), based on music from Spain, France, etc. XI-XIV ages. I liked Les Jongleurs de la Mandragore from Quebec, and some recordings from Dorian, even Azam Ali. Can anyone recommend anything else? My system is... too revealing, so the recording quality is critical.