Yeah, yeah, I'm a purist, too, but everyone's got at least one. I don't have many, but I've got two covers of Rhianna's "Umbrella" that I love (by All Time Low and Lillasyster), despite the fact that I hate Rhianna with a passion.
And, I gotta admit, it doesn't compare to the original, and I usually, for some completely unknown reason, dislike when girls sing Beatles songs (it doesn't make any sense, because I'm a girl), but Across the Universe's version of "I Wanna Hold Your Hand" is pretty adorable.
Be who you are and say what you feel because those who mind, don't matter and those who matter, don't mind
~Dr. Seuss