Favorite cover?

+1 for elliotbnewcombjr's pick of "Famous Blue Raincoat" by Jennifer Warnes.

I don't think Jennifer or that album got enough credit for reviving interest in Leonard Cohen's music. While there are a lot of great Leonard Cohen covers out there, my two favorites are Lloyd Cole's versions of "Chelsea Hotel" (from the "I'm Your Fan" tribute CD) and "Famous Blue Raincoat" (from the "Rare On Air - Volume 2" CD).

Rickie Lee Jones’ cover of Hendrix’ Up from the Skies on her album, Pop Pop.

Joan Jett "I love rock and roll" 

Speaking of Rickie Lee Jones... I love her cover of Steely Dan's Show Biz Kids.

Where to start...oh yes, Aaron Neville's "Everyone Plays the Fool", "It Feels Like Rain", well, the entire "Warm Your Heart" album is a sonic treasure trove!
Another surprise for me was the "Common Thread: The Songs of the Eagles" from about '93. A Who's Who of country stars of the time do a bang-up job on a selection of Eagles toons. Clint Black on "Desperado" stands out as does Vince Gills take on "I Can't Tell You Why". All quite well executed both creatively and technically.