Beautiful covers

I really like cover albums, because it's one way to judge the quality of a song.  Does it stand up to reinterpretation, new instruments, new tempo, a new generation?  Stardust is a timeless song; I'm a Barbie Girl, not so much.
Of course, this test relies on the cover version being an actual reinterpretation and not some tired rehash of the same arrangement that ends up sounding almost exactly like the original.  We have two new examples of really excellent cover albums:  Dark Hope by opera star Renee Fleming and Interpretations: the British rock songbook by blues artist Bettye LaVette.
Fleming avoids the mistake of turning rock songs into arias.  Her voice is rich and brilliant, but she doesn't overshadow the lyrics on songs from bands such as Muse, Death Cab for Cutie, Tears for Fears and Band of Horses.  Her cover of Leonard Cohen's ubiquitous song Hallelujah is beautiful (although I still prefer Jeff Buckley's version).  This is a very enjoyable album.
LaVette's album really demonstrates how much a song can be stretched, as she brings a bluesy feel to classic songs from The Beatles, The Moody Blues, Pink Floyd and Led Zepplin.  This isn't that dramatic a concept, as the British Invasion got much of it's inspiration from American rock and blues of the 1950's.....but she still makes it sound fabulous.  The first track alone - a totally funky rendition of The Word by The Beatles - sells this album.  And unlike many CDs, I actually found the liner notes for this one quite interesting.