Quite a few currently, all from the magnificent American TV show, The Wire:
Way Down In The Hole - all 5 versions, by The Blind Boys Of Alabama, Tom Waits - which is the original from the 1980s, The Neville Brothers, Domaje, and Steve Earle.
Assume The Position - Lafayette Gilchrist
Step By Step - now one of my all-time favourite songs, by Jesse Winchester
Feel Alright - Steve Earle
Fast Train, another stone-cold classic, by Solomon Burke
I Walk On Gilded Splinters - Paul Weller
The Body Of An American - a fantastic Irish-American song, by The Pogues
Efuge Efuge, again another great song, and entirely fitting, by Stelios Kazantzidis
The Life, The Hood, The Streets - Mullyman
The Fall - one of the greatest end themes for a TV show, by Blake Leyh.
I'll post video links to them tomorrow, if possible. Step By Step is almost impossible to locate, so not that one. If you've heard it, you don't need any reminding about it. It's probably one of your favourite songs as well.
And I gotta re-quote this, from MishoM. I don't think anyone noticed it before: