Wow, I came here to post this thinking it may be a deep track or something and someone beat me to it only 35 posts in. Bravo.
As far as the Dubliners version goes I can hardly understand a word they're saying cuz they blow through it faster than The Ramones. Although the do include the stanza explaining exactly what his girl did to betray him though.
Really? it maybe my passionate hate for 80's synthpop or the affiliation of the Gary Jules version to one of my favorite movies but I really like the cover more
Only two points. I think Jeff Buckley's Hallelujah is debatable. Also much like RATM, Metallica do a hell of a lot of covers that are better than the original. Garage Inc is a great collection.
Obviously Hendrix is the definitive answer. Fugees are a clear second.
Because he is Willie Nelson, any cover, of which there are many, have to be considered.
Even though he foisted upon the world a cover of the godawful "Unchained Melody", the Stardust album remains as one of the great collection of cover songs. Willie's interpretation of these Tin Pan Alley standards are, if not better than the originals, classics in there own right.
His cover of Kermit The Frog's "Rainbow Connection" is also worthy of consideration. A song that has been covered by many, Willie's version is so good that many people feel that he wrote it.