I can't get that song out of my mind either. After a little research on the web, I found out that it was a song called "Amazed" by Detroit-based singer-songwriter Mozella, who has a new album about to come out. See the following page for a little more detail, go down to the "Mercedes Takes to New $30 Million Brand Campaign" section. Hope this helps.

http://www.thecarconnection.com/index.asp?article=6970&sid=173&n=156