Stealing the title from a slot that Anne Nightingale used to do on her radio show years ago, to highlight similarities between disparate sounding songs, I'd like to suggest the following two -
Cathy Davey - Save Button (http://www.youtube.com/watch?v=9EKqDKeeFTI)
and
John Sullivan - Closing Theme to Only Fools And Horses (http://www.youtube.com/watch?v=uxOEhc960Bc)
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Slim Dusty [or any one of dozens of others, notably Rolf Harris, but couldn't find a nice recording] - Waltzing Matilda (http://www.youtube.com/watch?v=CwvazMc5EfE&feature=related)
and
London Symphony Orchestra - Pachelbel's Canon in D (http://www.youtube.com/watch?v=8Af372EQLck)