Racehorse: Cigar - someday I will get to Kentucky Horse Park to see him . Also love Tiznow, Silver Charm, Istibraq, Moscow Flyer and Hardy Eustace
Dressage: Anky Van Grunsven's Bonfire - no others need apply
Showjumping: Big Ben.. the old legend Hickstead, Cagney, Monopoly.
Eventing: Ready Teddy.
All other sports welcome, these are just the ones I thought of off the top of my head