For me, music has always been about the melody, with rhythm and beat falling far behind. Commitment is important, as is overall competence, but a great melody trumps all.
And I've always maintained that that a good song survives transformation; a great song will work in any format: country, rock, etc. Witness Johnny Cash's last albums of wildly divergent covers, done in acoustic Man in Black style. Or Glen Campbell's recent cover album Meet Glen Campbell: The Time of Your Life-Green Day, Walls-Tom Petty, Jesus-Lou Reed, all done with sophisticated modern pop/ country arrangements. Trust me, it works.
Check out this video trailer for the new album:
And this live video of "Time of Your Life" that sadly contains no Glen guitar licks:
And the dude is 72!
And now, for a new, perfect marriage of melody, rhythm, beat, commitment, and witty lyrics, here are The Ting Tings, doing "That's Not My Name":