@bigtwin - thanks for the Tom Scott cover, that was killer!
I could list hundreds of great covers, which I won't; but, here are a few that have been on my radar recently:
Judy Collins - Hello Hooray (Alice Cooper)
John Doe - A Case of You (Joni Mitchell)
Everything But The Girl - Alison (Elvis Costello)
Everything But The Girl - The Only Living Boy in New York (Simon & Garfunkel)
Marianne Faithfull - Ghost Dance (Patti Smith)
Hall and Oates - Standing in the Shadows of Love (Four Tops)
Hall and Oates - I'll Be Around (Spinners)
Bettye LaVette - When I Was a Young Girl (Savoy Brown)
Nouvelle Vague - Golden Brown (The Stranglers)
Linda Ronstadt - Ooh, Baby Baby (Smokey Robinson & Miracles)
Linda Ronstadt - The Waiting (Tom Petty)
Poco - Magnolia (JJ Cale)
Yes - America (Simon & Garfunkel)