Among my major favorites, is a lot of Beethoven, Bach, particularly Cello Suite 1, and Pachebel's Canon In D Major.
Many think of weddings with the Canon in D. I think of a hot day and a cool ocean, or watching the stars go by.
I especially love the mix of violin and piano, and the deeper tones at base... it brings a new layer to the higher sounds and they're not so "wimpy". (I'm better with bass notes.)
With no further ado: