Hawaiian music (not the orchestral kind) or mellow instrumental bluegrass is usually pretty good for that kind of stuff. Something that is string instrument based and kind of rolls along. I find Hawaiian is relaxing and puts a smile on your face at the same time.
Israel Kamakawikawole – “Somewhere Over the Rainbow”
or Eva Cassidy’s version is just as beautiful if not more so – she also sings a moving version of “Who Knows Where the Time Goes”