When you talk about this question you usually consider how good an athlete has been over a period of years.Now what Usain Bolt did was INDEED phenomenal, but this is his early stage.Michael Johnson was equally great, he also held records in 400M and 200 M, his 400M record still stands.The main consideration for ''Greater'' here is ''how good an athlete has been over a period of years'' because records will be broken owing to advancement in technology.Under this consideration Michael Johnson has dominated the track when he was there. Look at Asafa Powell, just a few months before the Olympics he was looking to the greatest, suddenly we saw Usain Bolt come out of the nowhere to do remarkable feats.How far he would sustain this form remains to be seen
So what do you think?

Jesse Owens is better than both of those two and the Berlin games!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!