Johnny Cash

Reznor was annoyed at first when he found out Cash did a cover of "Hurt" because it's a very personal song, but he said later that when he heard it that it blew him away and that he did a good job of it, so he didn't mind. Something like that, anyway.
 
when raznor first heard the song, he wasn't really blown away, but after he saw the video... everytime when someone asks raznor now about hurt he sais: "hurt is not longer my song" oO
 
I got into Cash about 6 months before the films release, but more specifically the American Recordings sessions he did with Rick Rubin. The cover of NIN's "Hurt" was the initial attraction but within these releases there are a bunch of re-hashed old cash songs, new cash songs (which are stellar) and some of the best covers you will ever hear, most notably Depeche Modes "Personal Jesus", Will Oldham's (Palace) "I See A Darkness" and Nick Cave's "Mercy Seat".

These are highly recommended releases but its also wise to check out his earlier stuff just because its classic essential listening for anyone with an interest in good music.