My favorite wedding waltz is the Irish one, I think it's called, "The Wedding", sometimes played after the wedding bands have been exchanged, "Here they stand, hand in hand, they've exchanged wedding bands, today is the day, they seal all their plans...May God bless, this couple, who marry, today..."
If you have a band, they can technically turn any song into a Waltz by changing it to 3/4 time. I've heard medleys of a song, "Amapola" comes to mind, where it starts out as a Rumba, turns into a foxtrot, then a swing, then back to Rumba, just by changing the timing.
I've been teaching wedding couples for 9 years, and have only taught about 4 waltzes. A pretty one was from Cinderella, "10 minutes ago". Another recent one was from West Side Story, "One Hand, One Heart" and of course Debby Boone's "You light up my life". You can look at my website at www.weddding-dance.com under the 'Congratulations to some of my couples" link for other ideas of songs, but most of them are Foxtrots and Rumbas.
All the best,
Lee Ann 