1. Beatles (no one even close to the impact and effect they had on me, the rest of the list is more categorical than anything else)
2. Steely Dan (and all the solo jazz/rock/pop artists they introduced, Tom Scott, Steve Gadd, Michael McDonald, David Sanborn, etc.)
3. Supremes, Temptations, Booker T. and the MG's, Four Tops, Stevie Wonder, The Rascals, Wilson Pickett, Otis Redding, (all the great artists from the Motown and Atlantic labels during the golden age of "soul."
4. Emerson, Lake & Palmer, Yes, Pink Floyd, Moody Blues (the "heady" rock)
5. Frank Zappa (bizarre but a true avant-garde composer)
6. Led Zeppelin, Rolling Stones, Cream/Eric Clapton, Jeff Beck Group; especially the album "Truth" featuring a young Rod Stewart on vocals who was actually the prototype that Jimmy Page found in Robert Plant when he formed Led Zeppelin a year later, of course Rod Stewart became a bigger (not better) artist (than Jeff Beck) in his own right.
7. Albert King, Allman Brothers, Marshall Tucker, Delbert McClinton, Howling Wolf, B.B. King, Doobie Brothers, Bonnie Rait, Little Milton, Bo Diddley, Stevie Ray Vaughn, Taj Mahal, Lyle Lovett, Susan Tedeschi (American music specialists who combined blues, country, gospel into their own unique styles and sounds)
8. James Taylor, Harry Nilsson, Elton John, Jimmy Buffett, (accoustical extraordinaires)
9. Dave Brubeck, Joe Sample, Peter White, Spiro Gyro, The Rippingtons, Stanley Clarke, Larry Carlton, Chick Corea (innovative Jazz greats IMHO of course)
10. Schubert (my favorite classical composer) all the other greats as well; Verde, Beethovan, Mozart, Chopin, Bach, Handel, etc. (These guys were a lot more interesting and unconventional than most people are aware of especially (again IMHO) Schubert who only lived to 31, existed mainly from handouts and by playing piano for tips in his local tavern, wrote his most uplifting pieces when depressed and his melancholy music when happy.