With 3 points in riding you can get a light warhorse, available at Braverock and other locales.
With 9 points in riding you can get a heavy warhorse, available at Mystdale castle, at the back of the stable--1st buy it, then sell it and buy the one that spawned in its place--very nice horse and the best you can buy.
With 72 points in riding you can get on 1 of the horses that later turn into a monster at that quest where the phony uncle asks you to find his niece (near Faerie's crossing). Do not take and do the quest afterwards or you'll find yourself riding a hostile lizard. Either of these 2 horses are basically invincible.
