Greatest Songwriter of all time


I was reading the Dylan post and it got me thinking. There are many great songwriters that come to mind, my expertise/knowledge is primarily with rock music. If you could only pick three, what would they be? My vote for best lyrics goes to:

Jim Morrison
Bruce Springsteen
Elvis Costello

Best music goes to:

Mark Knopfler
Stevie Ray Vaughn
Frank Zappa
jeffloistarca
the fab 4 beatles, bernie taupin who writes for all elton john songs, and the king elvis.
Warren Zevon
Van Morrison
Greg Brown
Arguably not the best, but my favorites.Agree with cfb, G. Clarks Cold Dog Soup is great and a nice tribute to the late, great Townes Van Zandt.
Comsider the following:
Patti Smith - Horses
Leonard Cohen - Any and all of it
Richard Thompson - Shoot Out The Lights
John Hiatt - Bring The Family
Laurie Anderson
Lou Reed