What the heck, here is my list for the ultimate 100m race:
1. Usain Bolt
2. Ben Johnson
3. Asafa Powell
4. Justin Gatlin
5. Bob Hayes
6. Tyson Gay
7. Maurice Greene
8. Donovan Bailey
All doing whatever they were/are doing, what a race!
Bolt--new standard setter
Johnson--old standard setter, never saw his best possible
Powell--given enough chances, as good as anybody
Gatlin--never saw his best possible
Hayes--never saw his best possible
Gay--with a start, as fast as anybody
Greene--not as fast as others, but a good racer
Bailey--with a start, as fast as anybody
Assuming the inconsistent or weak starters crapped out on the start, and assuming those from whom we never saw the best improved on their listed marks, I think it would be between Bolt, Johnson, Gatlin, and Hayes.
And when it came down to it, the three medallists would be Bolt, Johnson, and Hayes--the three guys who were head and shoulders above their contemporaries, who each had something special about their respective races, and who just seem to have that special ability.
The order? Bolt, Hayes, Johnson. The three best ever.