Here's one of my top 5 favorite songs of all time: Skip James performing Crow Jane. As you can probably tell by a quick listen, Mr. James isn't your typical bluesman. From his high pitched wail to his E-B-E-G-B-E "cross-note" open tuning that produces a more minor sounding theme, he was able to add a bit more sadness to your typical song about shooting someone "just to see her fall."
Enjoy.