I heard "Life Wasted" by Pearl Jam, and the first thing I said was wow this song actually has some balls. The big-time PJ fan nearby was offended, like it was some kind of revelation that most of their songs don't. :sleep
As far as great singers who can't sing, throwing Anthony Kiedis, Duncan from Snuff, Tim Armstrong, Chuck from Hot Water Music, and the lead singer from Q and not U into the mix.