Secretariat
The goddamn greatest racehorse of all time. Winner of the Triple Crown (Preakness, Bellmont, and the Kentucky Derby) in 1973, his performance at the Belmont Stakes is considered his crowning achievement. He ran the Stakes in a still-standing world record time of 2:24 (setting the world record by 2 2/5 seconds, or 10 lengths) and beating his nearest competitor by an astonishing 31 lengths. This discrepancy was so large that the widest-angle lenses could hardly capture both Secretariat and his competitors.

Named by Time Magazine as the #35 greatest athlete of all time (highest non-human).

Also the subject of an upcoming movie (2010).
Seabiscuit was the greatest horse ever!!

Man, you don't know jack. Secretariat is, and will always be, the greatest horse of all time. His records will probably never be beaten--the nearest competitor is still 2 whole seconds off!