I had to wash away that prior post/experience. Lucinda Williams has a uniquely scratchy voice - a "not great" voice - with a sweet smoothness to it. I saw her live at the Belly Up in Aspen a couple of years ago - she's a great live entertainer. Her lyrics are painful and heartfelt.
I'll give her my vote for the best female artist with the worst voice and the biggest heart - I love her. I love her funky, scratchy voice.
Here's another good one - "Passionate Kisses" ::
"Unsuffer Me" :: with tones that remind me of Neil Young on the guitar...
And my personal favorite :: "Righteously"