You might consider "One Hand, One Heart" from West Side Story, done acoustically. Neil Diamond recorded it on one of his more obscure albums. Also, Babs Streisand. My Irish band was asked to play for a wedding, and the Bride asked us to do this song, so we arranged it using a guitar and whistle and it was beautiful.

Also, Mairi's Wedding is a grand recessional. Listen to the Chieftains with Van Morrison's version on Irish Heartbeat (or is it Celtic Heartbeat?)

Mick