One of the greatest songwriters of all time, Randy Newman showed up on The Tonight Show Starring Jimmy Fallon last night and regaled effortlessly.   Just to get in the face of the NYC audience, Newman and The Roots performed a searing-guitar and horns-laden version of I Love L.A..   Then, as a web-exclusive, Newman performed a saxed-up version of My Life is Good.  Newman is out supporting his latest album, Live in London.   Check out the superb performances below, followed by the interview.  An American treasure.