Another one of those musicians I didn't instantly like, but am now in absolute awe with, is Ben Harper. I recently got hooked and soon after bought 2 of his cds that haven't often left my cd player since.
He seems to be one of quite few political songwriters left and I'm always happy to see when artists still use there power for a good cause.
I find that sometimes very openly religious artists can be a bit intolerant, don't worry though, this song proves Ben Harper is not like that.
He also tries out(and masters) lots of genres, sometimes reggae, sometimes almost country and sometimes just really perfect singer/songwriter material. Here are some of my absolute favorites: