According to "The Baseball Scholar"
Rickey Henderson is the unquestioned greatest leadoff hitter in baseball history. He led off in 98.3% of his career plate appearances. He had a .400 or better on-base percentage in 16 different seasons (1980, 1981, 1983, 1985, 1987, 1989 -1997, & 1999) and seven seasons with 100 or more walks (1980, 1982, 1983, 1989, 1993, 1996, & 1998). Henderson led the league in stolen bases 12 times (1980 – 1986, 1988, 1989, & 1998) posting 100 or more three times (1980, 1982, & 1983), while also scoring 100 or more runs 13 times (1980, 1982 – 1986, 1988 – 1991, 1993, 1996, & 1998). Rickey even brought power to the top of the order. His 293 career leadoff homers is 96 more than the second most. He holds nearly ever leadoff record in existences. As Henderson himself proclaimed, He is the greatest of all-time.
He has Ichiro 6th.
Full honesty here. I would have taken Ichiro had you not taken him right before me. But only because I'm not a baseball guy. Ricky is better.