1. Schubert - Ave Maria
(Hail Mary)
A lovely setting of the traditional Latin text. 
A good piece to have as the bride arrives, or to be sung during the signing of the register

2. Franck - Panis Angelicus         
 (Heavenly Bread)
A communion hymn sung in Latin, and usually
sung during Holy Communion.

3. Puccini - O Mio Babbino Caro from Gianni Schicchi
(O My Beloved Daddy)
A beautiful Italian opera aria, famously used in the film
A Room With A View.

4. Dvorak - Song to the Moon from Rusalka
A romantic opera aria from the famous Czech composer.
Rusalka the water nymph sings to the moon of her love
for a human prince.