Them and Abba.
As for "Hymn", Edguy's version has so much more soul than the Lunatica version. I can't believe they even did it after Edguy did it.
With "Dancing With Tears in My Eyes", it's interesting to hear both a prog version and a power metal version. Hard to say who did it better. Dreamscape really made it their own, as I had no idea it was a cover until I heard Freedom Call do it.