For me, hymns can reassure or inspire. "Oh God, Our Help in Ages Past" reassures me, while "How Can I Keep From Singing" inspires. I do like Melissa Nussbaum's suggestion of the Taizé "Wait for the Lord" for the communion hymn, but would hate having it repeated Sunday after Sunday as she proposes. Once every couple of months is enough. Perhaps she would also enjoy Fr. Chang's song, comprised solely of the verse "Thank you, thank you, Jesus", repeated. Very beautiful, in small doses.