Man there are so many wonderful love songs out there, and some great ones listed by others here. A few David and I picked to be played on our wedding night were:

Love of a Lifetime - Firehouse (this was our bride/groom dance song)

Masterpiece - Atlantic Starr

You're the Inspiration - Chicago

To Be With You - Mr. Big

Angel Eyes - Jeff Healy Band

There can be a couple different types of love songs, "new love" and "old love." One of my favorite "old love" type songs is Through the Years by Kenny Rogers.