I Gotta Right to Sing the Blues, duet with Tony Bennett

Tony Bennett, Playin' with My Friends, 2001

Maybe I'm getting old, but I have to say, I like this track. It's close to making my top 10 duets list. Yes, it's easy-listening lounge Bonnie, but her phrasing and guitar are spot on. Like the songs recorded with her father, John Raitt, this one brings out a side one doesn't often get to hear.  

I couldn't find a legit MP3 anywhere, but it's so good, you won't mind springing for the CD.   
          
Tracks with Bonnie Raitt

• I Gotta Right To Sing The Blues  

Separation Blues, duet with Maria Muldaur

Maria Muldaur, Naughty Bawdy & Blue, 2007

Separation Blues is Mama's Gone, Goodbye by another name. Both Maria Muldaur and Bonnie Raitt sang this song with Sippie Wallace; this duet is a tribute to that. It's a rather loose rendition that is interesting in the way it binds the three artists together.

Amazon doesn't sell an MP3 version, but iTunes does. 
          
Tracks with Bonnie Raitt

• Separation Blues  

Walking The Dog, duet with Weepin' Willie Robinson

Various Artists, Give Us Your Poor: Help End Homelessness, 2007

Walking The Dog is a fun, rollicking duet with Weepin' Willie Robinson, an at the time 80 year old homeless WWII vet and Boston blues legend. It's an original recording to benefit the Give Us Your Poor Campaign to End Homelessness. Details here. 

No longer homeless, he died a year later, in 2008. The Boston Globe has the story.
 
 
       
Tracks with Bonnie Raitt

• Walking The Dog  

Fats Domino Medley with Jon Cleary

Various Artists, Goin' Home: A Tribute to Fats Domino, 2007

Bonnie Raitt pairs up with Jon Cleary on a pair of Fats Domino hits from the '50s.Yet another sound!
       
Tracks with Bonnie Raitt

• I'm In Love Again / All By Myself  

Crepuscular Solidao, duet with Cesaria Evora

Cesaria Evora, Sao Vicente di Longe, 2001

How's this for different (and obscure), a duet in Portuguese with Cesaria Evora, the Barefoot Diva of Cape Verde? It's outside of Bonnie Raitt's wide-ranging repertoire, but she pulls it off.
       
Sadly, Cesaria Evora passed away in São Vicente in December, 2011.

Tracks with Bonnie Raitt

• Crepuscular Solidao (Twilight Loneliness, duet)  

It's a Blessing, duet with Maria Muldaur

Maria Muldaur, Richland Woman Blues, 2001

Here's a different sound: Bonnie Raitt, Maria Muldaur, a guitar and a Delta Blues spiritual. The song came to Maria, as she tells the story, from an old recording of Bonnie Raitt's mentor, Mississippi Fred McDowell singing it with his wife, Annie Mae. It's such a gem that it appears on 3 other recordings: Where We Live (2003), 30 Years of Maria Muldaur: I'm a Woman (2004), and Blues Guitar Women (2005).  

Tracks with Bonnie Raitt

• It's A Blessing (duet)  

Do I Ever Cross Your Mind, duet with Ray Charles

Ray Charles, Genius Loves Company, 2004

Here's another great Bonnie Raitt duet, this time with Ray Charles on his last album before his death. Great track.  

Tracks with Bonnie Raitt

• Do I Ever Cross Your Mind (duet)