Way back in 1997, we had some fun with the original and English versions of Pirate Jenny and Mack the Knife. Brecht's originals are some of the most powerful German I've read. The "standard" translations by Marc Blitzstein lose some of the evil power of Brecht's words, but I still think Blitzstein did a great job.
Blitzstein, by the way, is one of the main characters in the film The Cradle Will Rock, a story of the Federal Writers' Project of the 1930's.