Eva Cassidy--"Live at Blues alley". The rest of her catalog is pretty special too. If yuu don't have something by her, you are missing something special.
I also can go a month or so and not listen to Jennifer Warnes "The Well", but when I do play it again and give it a good listen, I wind up listenig to it regularly for the next 3-4 weeks--like almost for the first time.
I don't think I will ever tire of these ladies' voices.