To add another list, here's the RING Magazine's listing from September 2002:
1. Ezzard Charles
2. Archie Moore
3. Michael Spinks
4. Tommy Loughran
5. Bob Foster
6. Jimmy Bivins
7. Harold Johnson
8. Maxie Rosenbloom
9. Billy Conn
10. Matthew Saad Muhammad
11. Victor Galindez
12. Jack Dillon
13. Battling Levinsky
14. Joey Maxim
15. Dwight Qawi
16. John Henry Lewis
17. Bob Fitzsimmons
18. Gene Tunney
19. Virgil Hill
20. Marvin Johnson
Honorable mentions: Paul Berlenbach, Georges Carpentier, Jack Delaney, Gus Lesnevich, Lloyd Marshall, Henry Maske, Freddie Mills, Eddie Mustafa Muhammad, Battling Siki, Prince Charles Williams.
Here's my go:
1. Ezzard Charles
2. Archie Moore
3. Bob Foster*
4. Michael Spinks
5. Gene Tunney
6. Tommy Loughran
7. Harold Johnson
8. Maxie Rosenbloom
9. John Henry Lewis
10. Billy Conn
11. Jimmy Bivins
12. Harry Greb
13. Jack Dillon
14. Joey Maxim
15.
Tommy Gibbons (a guy the RING completely overlooked, you guys didn't

)
*quick note:though Sam Langford was built as a LH and fought at around 170, he was fighting the heavies of his day, never really fighting any LH's. I exclude him from my listing of LH's, but if I included him, he would be here.